Metal in Jewellery

I promised yesterday that I'd go into a bit more detail. This won't be too advanced, so don't worry, but I do ask you to just have a quick look at this, a chart you may remember from school.

You can click on it for a better look, but briefly, all the orange and light blue squares are metals, as are some of the others. There are a LOT of metals, in fact most elements that occur naturally are metals.

But for the sake of this article we don't need to worry about many of them. They simply are not used in the jewellery industry, or so rarely that you are unlikely to come across them.

When people think of jewellery they usually think of two groups. The first is precious metals (silver, gold, platinum, rhodium, and palladium). They are precious because they are rare, and consequently expensive. Wars have been fought over silver and gold, and many lives lost.

Gold stays shiny and bright without tarnish for centuries (forever, pretty much), and it was this property that first attracted us to it. Silver, on the other hand, tarnishes quickly and is less valuable but still extremely important and desirable.

Beginning way back, jewellery has also been made from other metals often known as base metals; this is our second group. These include copper, iron, and tin. The term "base metal" is a bit of a misnomer as it properly only refers to metals that react with hydrochloric acid, but it's used informally to describe the common metals that are not precious.

Early in human history we discovered that two or more metals can be mixed together to create alloys that have the best properties of each. You may have heard of the Bronze Age......

Bronze was initially made from copper and arsenic, and subsequently copper and tin, and was a revolution, being harder than either of them and incredibly useful for just about everything. Weapons, jewellery, and some of the earliest construction hardware were made from bronze, and when it was discovered that it stood up to saltwater, it was guaranteed a place in our seafaring world long after iron and steel had replaced it for other uses.

Today bronze often includes silicon or aluminum, and other mixtures such as copper and zinc have been used for a long time. Indeed many other metals, sometimes more than one, have been added to copper to create bronze. It's therefore not a strict recipe. This is important to understand, because questions such as "What is bronze made from" really have no single answer.

Which brings me to today's costume jewellery alloys. The debate still rages over these, despite many reassurances from manufacturers that toxic metals are not included and I've dealt with that separately in an earlier blog. Some of the fuss is pure snobbery. Silversmiths look down their noses at costume jewellery, especially if it's mass produced. I believe if you like a thing, you like it, and everything has its place.

The simple fact is, the superiority of a metal is relative to its purpose. For an heirloom piece it makes sense to use a precious metal. For everyday fashion jewellery it does not. Many of the modern alloys retain their looks without cleaning, and busy people do not want to be forever attending to the oxidization of their jewellery. If you want a valuable item, that you can resell later if need be, then certainly, buy gold. But if you just want something you can discard at whim as the fashion changes or you bore of it, it makes absolutely no sense to spend large amounts.

A greater concern, surely, is allergies. It is the inclusion of nickel that is the usual problem. While it is still widely used, public demand seems to be affecting that quite powerfully. Some countries even restrict the use of nickel. Manufacturers in the Far East really have no choice but to follow this demand if they are to stay in business, so increasingly nickel is found less and less in jewellery, restricted to the cheapest end of the market.

So what is your costume or fashion jewellery made from?

There are several types. Very light jewllery is often made from aluminum, or an aluminum alloy (with silicon, etc). Although there is talk of world shortage, and consequently it's not as cheap as it once was, there is plenty of it on the market. Aluminum is very easy to colour by anodizing and it doesn't tarnish. We have tested anodized aluminum inadvertantly by losing it under a pile of snow for months. It didn't change at all. If you want a real carefree material, this is your first choice.

However, this light weight can put some people off. The look and feel of the heavier alloys is desirable and this is the reason that plated metals are so popular.

It surprises many people that many components of plated costume jewellery are often iron, with a reasonably thick plating of a more resiliant alloy, or a light plating of silver, or sometimes even gold. It's not hard to discover which pieces have iron at the centre as they are magnetic. If the plating is good, these are perfectly serviceable for some time, and vintage pieces are easily found on the market dating back many decades.

Slightly upscale the central core could be brass. I've had many people tell me their bass based components are finer as they are not magnetic, as if iron is somehow a "poor" metal to use, but just as the rust can break through the best plating if an item is allowed to get damp, green corrosion can occur on brass based items under damp conditions just as quickly. The answer is to keep it dry.

Brass itself is similar to bronze, but is usually a mixture of copper and zinc. There is a lot of overlap here though, and the distinction between bronze and brass can be arguable.

For that reason modern bronze jewellery is often "actually" brass, but with other additives to enrich the colour, so it's really strictly neither one nor the other. As I stated earlier there is a lot of variation in alloys, both in composition and ratio, and it's hard to pin definitions down.

The most popular alloys on the market today are the zinc based, antique silver coloured pieces known frequently as Tibetan silver or "silvertone". Once upon a time there was a silver alloy made in Tibet, and there still is, in very small amounts. The vast majority of Tibetan silver on the market today contains little or no actual silver (except sometimes as a plating) and the name is simply a convenient trade description.

Zinc and what then? This varies a lot. Like pewter, which is very similar, it can have a number of ingredients, and one of them was typically lead. Due to public demand this has been removed from the recipe by most manufacturers. Copper is less common these days as prices rise, although the weight of many pieces makes its presence felt, and increasingly nickel is being replaced by iron, to prevent allergic reaction. Therefore your magnet test may well pick these up. But there is no hard and fast rule, and most observers believe the metals used are at least partially decided by price and availibility.

The benefits of these modern alloys are obvious. They are both inexpensive and easy-care. So long as you don't store them in damp conditions they will last for decades, even long after you lose interest in them. If the design is timeless they can become favourites just as easily as expensive pieces. I have been making costume jewellery since 1991, and pieces my friends had at that time are still being enjoyed. This isn't throwaway jewellery.

There is a tremendous difference between the quality of mass produced fashion jewellery, and carefully hand-made costume jewellery. In fact, I may be accused of bias, but I would go so far as to say that the care and attention to detail in small scale production costume jewellery makes it superior than mass produced mall jeweller "fine" jewellery. Quite apart from anything else, the uniqueness of the piece beats "everybody has one" of the mall jewellers' sterling trinkets, hands down.

I'll just touch briefly on two other metals you may come across, titanium and niobium. These have become extremely popular in recent years for their zero allergy reputation, and the effect anodizing has on them. An electric current will change the surface colour depending on voltage. Titanium has spectacular, bright, almost garish colours, while niobium is more subtle. Neither will tarnish and consequently they are increasingly being thought of as an alternative to precious metals.

Stainless steel and surgical steel are often considered good choices, for appearance and durability, but they are very hard to cut, which is part of the reason for higher prices. Still, they have nice bright finish, which like the other alloys, requires little attention.

Finally, tungsten carbide (not an alloy, but a chemical compound, only the tungsten being metal) has taken the market by storm for it's hardness and durability, which surpasses that of gold. The downside being, if it is broken, it's not repairable.

When you choose a metal the important things to consider are:

How often will I wear this?
How much do I want to spend?
What "look" am I aiming for?

The three often have to be juggled a bit.

You know my mantra by now...jewellery is to be enjoyed. Its value is in its appearance. Although we have spot prices on gold these days, it is not truly worth anything unless people want it. Beauty is in the eye of the beholder. That's you. Buy what you LIKE.

Giving Jewellery As A Gift

It's that time of year, and whether you were planning on buying from me, another small business, a cheapy import from the Far East, or an over-priced shop in the mall, or even making it yourself, the same question arises, what would she like?

Sometimes it's really hard. I've been making jewellery for over 20 years now, and I am no closer to reading minds than I was before I began. Tastes vary.

Not only that, people change. What was eagerly received ten years ago might not be now. Fashions change, obviously, but people are just at a different stage in their life. The student who loved hippy beads is now a businesswoman and would prefer something more classic.

So where do you start?

First things first. There are two fundamental things you need to know before anything else:

Is she allergic to any base metals? You may be able to tell simply because she never wears any. This doesn't mean you are restricted to silver and gold, read on.

Does she have pierced ears? If so are they regular piercings? There is no point buying standard 20 or 22 gauge wires if she has stretched holes.

If she has no piercings, don't just assume you can buy clip-on earrings as many women find them uncomfortable.

So far so good. Most women with no allergies and pierced ears like jewellery.

Let's consider a few guidelines here.

Is she conservative in her overall look?

If so, you will not go far wrong with a string of semi-precious gemstone beads, not too large.

Oval beads around 15mm in length, alone or in combination with other, smaller beads, are extremely useful as well as attractive, and will work for business clothing as well as more casual.

Is she a very girly girl?

Then buy crystals, and stick to pastel colours.

Is she artistic herself?

Don't be afraid to choose for her, in fact she'll probably value funky choices even more than the average person. And she'll definitely prefer handmade.

Is her appearance important in her job?

Then buy a matching set rather than random items, to help her with her "put together" look.

Is she very fashion conscious, keeping up with all trends - and you are not?

Don't worry. Sellers do keep up with trends. If you buy from anyone's most prominent position, it will be a popular item.

Does she already have a lot of jewellery?

That means she likes it.

Does she work with her hands?

In general avoid bracelets and rings.

Does she work with children or animals?

In general avoid very long necklaces, or very dangly earrings.

What about older people?

Even old ladies in nursing homes still like to look pretty. Get her something with an easy clasp for old hands.

What about colours?

When in doubt buy for the season. Sparkly cheers up Winter and works for holiday parties etc. Once Spring comes around people are looking for fresh, natural colours. Come Summer they want a bit more colour, possibly even tropical colours if their personality is fairly extrovert. As summer ends, earthy and Fall colours appeal.

Should I choose her birthstone?

It usually goes down well, but she may already have enough. Try that colour in other materials or the same stone in less obvious ways, such as rough tumbled beads on a bracelet, rather than the usual cut stone.

I know her favourite colour, that's safe isn't it?

Fairly but not certain. There are many shades of blue, for example and a lover of turquoise may not necessarly be into cobalt. Unless the favourite shade is known, that's an easy rabbit hole to fall down. Consider style first.

What do you mean by style?

Let's consider several girls.

Susan wears jeans and t-shirts a lot, works with horses, like to cycle, and usually keeps her hair tied back. You know she likes jewellery, but she seems to be quite understated with it, to avoid fuss.

She will probably be thrilled to bits with a simple necklace, a gemstone or other pendant, on a light chain, which can just dress her up without a lot of effort. Go for unusual and interesting without being outrageous.

Karla works in an office and has a very busy life. She doesn't have time to mess around with matching things.
Buy her neutrals, pearl beads, or clear crystals, fairly classic and simple, and make sure the clasps are easy to do.

Helen has a hectic social life and is out several nights a week. Bit of a party girl. Buy her bright, bold colours that make a statement. Watch what celebrities are wearing, but don't copy it slavishly.

Linda is a redhead. Buy her denim blue or sage green jewellery.

Gina has been having hard times for a while. She can't afford to dress up or go out. A pretty bracelet will make her day, and she can enjoy it anywhere. Any woman who is short on jewellery will value it, but she may be afraid to wear expensive looking items as it will highlight old/worn/cheap clothing. Stick to casual, fun styles.

Your sister. She's a pain to chose anything for. She's very fussy and seems to change her mind a lot. Buy her the classic "two round gemstone beads on a wire" earrings. They look good on anyone, in any situation, and often become favourites. Make a note of the colours of clothes she wears.

If she likes blue, buy lapis, blue goldstone or turquoise.
If she like pink buy rose quartz.
If she likes purple buy amethyst.
If she likes neutrals buy tiger's eye or jasper.

If in doubt buy black onyx.

Your mother. She already has boxes of jewellery she never wears.

Go with personal. Find something with her initial on it, or something which will trigger happy memories. If you once had a fantastic holiday at the sea together, buy her seashell earrings and remind her of those days.

Your daughter. Impossible. She buys new things and tires of them quickly.

Buy something of medium value (sterling silver, gemstones) and include a sincere note. She'll wear it forever.

Your best friend. You know her tastes, but what would be different? Try chainmail. It comes in all colours and there really is something for anything there.

I mentioned earlier about metals. In my next blog I'm going to go into great detail about this, but meantime I just want to remind everyone to think outside the box. Jewellery can be metal free. Consider leather, hemp, silk, and cotton. They need a bit of care not to get dirty, but these are perfectly acceptable as jewellery.

Cost of Shipping

With so much shopping being done online now shipping costs have become a talking point among buyers and sellers alike. The postal services charge far too much, and still don't seem to be able to make a profit. I suggest they need better management, but that's not my problem, and there's nothing I can do about it. But from your POV........



1. Buy several items at once from the same supplier and you will usually save money. The actual  postage cost works out cheaper by weight as parcel size increases, therefore most online sellers offer discounts, not just as incentives for you to buy more from them, but simply because they can.

2. However, there is an exception to this. Import duties are often waived on low value packages (check the tariffs that applies for your country) and paying for shipping several small packages may then end up being cheaper at the receiving end, than paying the duty on big one. It's worth spending a little time calculating the difference.

For example, assume duty is waived on packages valued $20 and under. You have ordered 3 items, and the package is valued at more than $20, but each item individually is valued at less than $20. Shipping costs $10 for each item separately, there is no duty on any of the packages, therefore you would pay a total of $30 shipping.

But, let's say the shipping is discounted to $15 when all items are sent together. However, when the package arrives, there is duty to pay of $10 on the goods, and brokerage fees with taxes on top that (normal) - another $10. Your actual shipping costs are therefore $35. It would have been better to have the 3 items shipped separately. As every case is going to be different you will need to educate yourself, and do the math to save money.

3. When is it cheaper to have an item shipped rather than go to a store and buy it?

There's a bit more math involved here too. It all depends on how far the store is, what gas mileage your car offers, and so on, against shipping costs.

For example, if you can walk to a store that you know will stock the item you need at a fair price, buying it online makes no sense.

But just this week I bought a bottle of nail polish online. How does that make sense?

Well, the shipping cost was $2. For me to buy that bottle of nail polish, at the same actual cost, would involve a minimum journey of 20 miles. That is assuming they have what I want there, and I don't know if they will. So it could involve more shopping around. In fact I could end up spending 3 or 4 times as much on gas to find my nail polish "locally" than by having it mailed from another country. Yes, it's mad, but that's how it is.

Of course, if I was to pick it up when I was shopping anyway, I could offset that cost by spreading it over all my purchases. So that must be considered too. The question is, when I go shopping, do I/will I remember, have time for, or be able to find all the items I might otherwise buy online? This is what we have to ask ourselves. Only honest answers count :)

Black Gemstones

The commonest complaint I get from customers is that their black onyx is black onyx.

Before your face contorts with trying to rationalize that, let me remind you that gemstone nomenclature is about fashion, not minerology, and you can read my other posts on this subject to learn more. What a gemstone is known as in the fashion jewellery industry can mean many different things, and sometimes, well, let's face it, sometimes it's fake.

Black onyx doesn't exist in nature. There are very dark charcoal grey onyxes and very dark charcoal grey banded agates (I'll come back to that later) but not solid black. Not really black. It just doesn't come out of the ground like that. If you want a "natural" solid black gemstone, you should choose instead obsidian or jet. But not all obsidian is black either, and even when it is, if you hold it up to the light you will see it's really a very dark brown. And jet is coal, actually. So it really is black, but it's not a gemstone. And, before we muddy the waters even further, French Jet is...glass. But then, so is obsidian...it's volcanic glass. Have I lost you yet? Oh dear! You begin to see why this needs a whole blog.

If you want the look of solid black, choose any one. But understand their limitations.

Most black onyx on the market has been dyed to make it blacker. This is what the customer wants, solid black, no white or grey bands. I buy my black onyx undyed, and then I select from it the pieces with minimal banding and "off" colour. The blackest ones I sell as black onyx, the banded ones I sell as striped or banded black onyx. Sometimes the blackest ones have a very faint banding, and sometimes it only shows up in really bright light. Inevitably, some people object to this. Personally I think it's lovely, and the majority of my customers do too, they are delighted with this subtle "imperfection" and probably surprised too.

The question then, is how you, who are not a gemstone expert, can tell the difference. 

First, I must ask you why you need to. If you like what you see in front of you, presumably you bought it because of its appearance. These are not valuable gemstones, and not rare, there is no investment motive to buying them. If they look good, and serve their purpose, does it really matter if you got black onyx instead of obsidian, or vice versa? I can understand you being upset if it turns out to be glass, but that's much easier to determine, and you know, even then, black glass is a modern miracle, and it can cost as much if not more to produce than regular grade onyx or obsidian. It's only made because of its regularity, i.e. you can guarantee the end result. 

The exception would be those who follow crystal healing practices, however I would suggest that if they can't tell that obsidian isn't crystalline, they're probably charletans anyway. 

Glass or jet is easily recognized by a simple scratch test, and this will permanently mark your stone, so either do it on the back, or be ready to accept the consequences. Scratch tests, you may remember from school, are where a harder mineral will scratch a softer one, with the harder one remaining unmarked. To tell between glass and jet, float it. Glass will sink, jet (which is related to amber) is light, and will float. 

Onyx and obsidian also sink in water, but will not scratch easily, and that's despite obsidian being a type of glass. It is much harder than, for example, bottle or window glass, and will not be scratched by these.

When it comes right down to it what we are really asking here is how to tell between onyx and obsidian.

#1 Obsidian is never banded. If you see any hint of a stripe when it is held up to a strong light, it's not obsidian. It may however have tiny "bubbles" if you have a jeweller's loupe or other strong magnification available.

#2 If you actually have a powerful microscope handy, you can see an obvious crystal structure in onyx. Obsidian, being a type of glass, has no crystal structure whatsoever.

#3 If you have both, comparison can be done. Obsidian is naturally brighter, again, because it is glass.

#4 If the two pieces are the same size (for example, two 8mm beads), the onyx will be heavier.

#5 If you only have one piece, nothing to compare it to, and see no bands, it is not easy to tell, without experience. It is probably safe to say that if you hold it up to the sun (carefully, blocking the light fully) and it still looks opaque black, you do not have obsidian. What you have is also probably dyed.

However it may not be black onyx. It may be black agate.

What's the difference?  Well......Onyx is a type of agate. It is therefore always correct to call onyx agate, but not necessarily correct to call agate onyx. It's a subset, not a synonym.

Onyx has finer crystals than agate, they are called microcrystalline. This results in the familiar bands being very regular. If dye has been used, and bands are hard to see (to the naked eye they may not be seen at all) then telling onyx from "just agate" is virtually impossible without a microscope. If bands are present, you can use those as a guide. Banded agate is still lovely, it's just not quite as "fine" as onyx.

I'm sure you'll be browsing Google images now, so I'll leave you to it :)

Hand-Made

Those of us who make and sell things for our living often talk among ourselves, and we laugh a lot about the descriptions used by people who are perhaps more affected than we are. 

I bought some "amber" chips from a supplier in the US last year, only to discover they were coloured glass. In fact they look like broken beer bottles that had been tumbled. A friend suggested I sell them as "upcycled" beer bottles. They'd probably sell too. But I would feel deceitful doing so, even though it's not actually wrong. 

This sort of thing bothers me, which is why I'll never be rich, but I sleep soundly at night. For me, business ethics includes not just honesty, but being realistic. 

Today I want to alert you to a common practice in marketing costume jewellery that isn't illegal, and not necessarily unethical, but caveat emptor, just be aware. 

A favourite term known to attract interest is "hand-made". All jewellery is hand made, with the sole exception of chain. Chain is made by machine these days (unless stated otherwise, when it becomes chainmail, and you can easily see the difference). 

Yes, the component parts are made by machine. Wire is drawn by machine, metal beads are stamped out, other beads are cut by machine, charms are made in moulds. I can even show you how earwires are made. Here's the gadget:

http://www.gossamerwingsdesigns.com/ear-wire-maker.htm

Of course there are bigger, semi-automatic versions of that.

So, here's the question, if a person uses that gadget, and makes them one at a time, but lots of them, are they hand-made or mass-produced? The answer is both, which really goes to show how useless these terms are.

Having been made by machine, large or small, one at a time or many, the components are assembled. There are certainly tools used, but every aspect of every design involves a human turning, threading, cutting, and most importantly selecting components to create a design.

The photo at the top (please click on it to enlarge it) shows the process involved in making a pair of dangly earrings. All the bits and pieces you see were made by machine. Even the crystals are cut by machine. But having created a design, I select the parts required, count them out and then put them together.

So, when does hand-made become mass-produced? Is it to do with quantity? Speed? I think that's a personal judgement. If I make six pairs at once that seems to be OK. If a girl sits in a factory in China making the same design for weeks on end, as fast as she can, maybe 3000 of the same design, is that NOT OK? Has the Chinese girl become a machine? Even if I only make one pair, what is the significant difference, why would that be hand-made and one of the 3000 not be? It's all assembled the same way. And I assure you, it is no different if she is supplying a dollar store or Calvin Klein.

Perhaps the care and attention to detail involved when I make a few at a time makes it different. It is the only difference I can think of.

When I describe something as hand-made it is because that is significant. For example I use glass beads that have been made by hand rather than in a machine, these are all unique, and rather interesting. Millefiori, lampwork, etc. Some are ceramic, painted by hand.

My daughter often makes her own clasps, to use on chainmail bracelets and necklaces. Again, these are different to those made by machine, and the description is significant.

But if you ever see anyone describe earrings as hand-made, that are assembled from parts that are not of themselves obviously hand-made, it's a good idea to ask yourself why. What are they trying to say? What other misleading information will they give you? How much extra are you being charged for a meaningless "quality" and are you going to allow yourself to be swayed by fancy words?

Anodized Aluminum

I'm here today to make a report on an unplanned experiment!

Last year, in September, if I recall correctly, Rhiannon made some chainmail Christmas Tree earrings and we put them up at eBay.

I took them outside to photograph them, as it was a nice sunny day and we always get better results taking photos in natural light, but as it was windy, I had to do this on the porch. So I used the wooden bench out there as the background. It worked well, I took photos of several other designs as well, and in moving things around I must have dropped one of the earrings. I wasn't aware of it at the time, but noticed I was one short when I went to sell the last pair. I had to get Rhiannon to quickly make me more.

Yesterday we were sitting out on the bench enjoying some sunshine, wrapped up well as it's still chilly here, and I saw something colourful lying in the snow. It was a Christmas Tree earring!

Despite being out in the cold and wet for 6 months, it had stood up rather well. We have never tested our earrings in this way on purpose. We rather expect people to keep them dry.

So we were not surprised that the earwire itself was damaged. They are rhodium-plated steel, and there were signs of rust. After 6 months in the snow, I fully expect this. The message here is don't leave your earrings out in the snow for 6 months, as rhodium-plate can't hold out in those conditions. But it's not expected to.

What was amazing however, was that the anodized aluminum chainmail rings had come to no harm whatsoever. Of course aluminum holds up well in bad conditions such as wet. It doesn't oxidize. But 6 months of snow and sunshine hadn't dulled the colours at all. This is performance beyond expectations, and is really quite exciting. What it means is that given the care one normally provides jewellery it will stay looking brand new for many decades. I think we can now safely consider anodized aluminum to be a "heritage" metal.

What's In A Name?

After reading my blog on amethyst, in regard to "green amethyst" being a misnomer, I was asked "I've heard of a green sapphire, is that wrong too?". There's no straight answer to that. The term is certainly widely used and accepted, but the naming of gemstones is complicated.

Sapphire, by definition, is normally a blue stone, in fact that's what it's name means. It's the blue form of corundum, which like many gemstones, can certainly come in other colours, but when it does, we sometimes give them other specific names. If corundums are pinkish red we call them rubies, for example. Certainly, corundum can come in green, and other colours too, it all depends on impurities. Therefore a green sapphire is a rather confusing term to use but it's all we have (for now) and it's just one example of why arguments about names of gemstones are common, and can sometimes get a bit silly.

Many minerals, including corundum, beryl, quartz, and others, when pure, are actually colourless, but impurities such as iron, chromium, copper, and so on, cause coloured varieties. Colours can also be changed artifically in some minerals by heat, irradiation, or even dye. So if you use colour as a guide for the name, it could, theoretically, change name if it changed colour. Hmm.

It gets even more complicated on an international basis. When people think of jade, they usually think of a green stone. In fact a common name for jade in some countries is..."greenstone". But jade can come in many different colours. Then there's the issue of what precisely jade is - several different minerals are known as jade quite legitimately, and quite a few more simply "in the trade". In fact a definition of jade, if you want to be accurate, would necessarily take several paragraphs of explanation.

It's no wonder then that potentional buyers almost need a course in gemology. Then, popular names change with "trends" anyway, so you still have to keep up.

A popular gemstone recently is "mystic topaz". To be harsh, this is fake coloration. However, the process used is really not any more extreme than other common and accepted processes in the industry. Clear topaz is coated with a layer of titanium. You may be familiar with the rainbow effects from titanium, well, this is the rainbow being seen through a faceted clear stone. The effect is really quite something. When a customer in a jeweller's store asks if the stone is genuine, he will be told yes. It is, after all, real topaz. And a titanium coating is no different to the rhodium coating applied to many high end rings.

If instead he were to ask "is it pure?" he might get closer to the truth, but what is "pure"? As noted above, the colour of a gemstone is created by impurities.

A better question, if it matters to you, is to ask if the coloration is natural. There is a better chance of a straight answer then, but no guarantees. Salesmen can have creative ideas about what "natural" means too.

So why does a treated topaz get a fancy name like "mystic" while a naturally occuring gemstone like green sapphire gets nothing? In a word: marketing. Back when sapphires and rubies were first found, nobody knew they were the same mineral. At that point in time, if a green sapphire had been found, it would almost certainly have been called an emerald. And why not? Even today the word  for emerald in some languages is the same word as that meaning "gemstone". At least when we say emerald, we are expecting green.

Confused yet?