AZGem Gems
April, 2001

The World's Most Useful
Gem & Jewelry Monthly Newsletter

Written by Carolyn Doyle for customers of
The Dorado Company
and other visitors to the website who subscribe.


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Usable Gems... and a little opinion.

Gems, Gem Stones, Colored Stones

What is a gem?

Why are gems called "stones"?

What is a colored stone?

All good questions that I've been asked many times. And as you would expect, I have answers!

Both the questions and answers are in the context of jewelry use...


What is a gem?

To paraphrase the U.S. Federal Trade Commission, a gem is a ruby, sapphire, diamond, pearl, emerald, topaz, or other product of the gem industry, which possesses the beauty, symmetry, rarity, and value necessary for qualification as a gem.

Simple, huh?

An inexpensive garnet can be a real gem, and a one-carat diamond can be worthless. To me, being a gem has much more to do with pleasing the eye than being worth a lot of money.

Low quality diamond is used in drill bits and saw blades. Low quality garnet is often used in place of sand in public ashtrays. And low quality ruby and sapphire is used in sandpaper.

The gem industry uses the higher grades of these and other materials as gems… most often to be set in jewelry pieces.

In addition to the requirements set by the U.S. government, another criteria some would add is that a gem must be natural.

By "natural" most people mean to exclude stones produced by man in a laboratory, even if they are chemically and visually the same as the natural gem stone.

These stones are commonly referred to as synthetic stones, or synthetic gems, and are often used in jewelry.

By natural some mean a stone that has not been color or clarity enhanced. Some serious gem collectors reject stones that have been heat treated, irradiated, oiled, or otherwise enhanced.

Gem collectors do approve of cutting and polishing the natural stone. Many mineral specimen collectors reject all intervention by man beyond cleaning what is dug from the ground.

Gem Stones

Why are gems referred to as stones?

Because they're made of minerals… except for pearls.

All of the gems that come readily to my mind are made of two or more minerals.

I know, diamonds are made of "essentially pure carbon." But even with diamonds a few atoms of other minerals sneak into the stone's crystal structure, often giving the diamond a hint of color.

How about corundum? Corundum is made of aluminum and oxygen. Add a little titanium and iron and you have blue sapphire. Add chromium instead and you have ruby.

While we think of aluminum as a light and somewhat soft metal, corundum is the hardest material known other than diamond.

Quartz is made of silicon and oxygen. Mix in a few atoms of (ferric) iron and you have citrine.

So most gems, like rocks in your garden and the pretty rocks collected by rock hounds, are made of minerals.

Colored Stones

What is a colored stone?

All jewelry stones other than diamonds are collectively called colored stones.

Although the organic materials coral, amber and ivory aren't made of minerals, they are included in the trade term "colored stones."

But some other jewelry materials are not included in the colored stone classification.

Feathers, seeds, shells, and artificial stones such as glass and plastic aren't included.

Among the colored stones there are so many common traits… and exceptions to the rules, that we can talk about, but that must wait for another newsletter.

Big Studs

If you haven't checked out the 7-mm stud earrings featured on our website, please use the link below to do it now.

The earrings are great, and so are the low prices!


Free Shipping

Don't forget, we're offering free shipping on all orders over $99.

Just deduct the shipping charge when you fill out the order form. If you forget, we'll deduct it for you.


Until next month…

please, visit me anytime at for a great selection of colored gems at great prices.

Carolyn Doyle

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The Dorado Company
P.O. Box 8232
Scottsdale, AZ 85252-8232