AZGem Gems
January, 2005
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.


Play of Color Gems


play of color gemsPlay of color gems are the subject of this month's newsletter, the third in a series on optical phenomena gems.

Play of color gems are well named as you can see in the black opal example shown here.

Either of two optical phenomena can cause certain gems to exhibit a rainbow of colors unrelated to the gem's own body color... interference and diffraction. This just means that the color phenomena is caused by something in the gem's structure.

In gemology speak, the colors produced are known as interference colors or  diffraction colors.

A discussion of the way these types of colors are  produced gets somewhat involved. For our purposes lets keep it simple and talk about the stones that display these optical phenomena.

Opal is the best known of the play of color gem stones. Opal is made up of tiny spheres of silica with minute amounts of water and air trapped in the spaces among these round spheres.

Light passing through the stone can be broken up into various colors. The size and arrangement of the silicon spheres influence the colors seen. 

As noted above, the opal shown above is called a black opal... for obvious reasons. The opal shown here is known as a white opal.

The points of color displayed in opal is known as "fire."

Opal comes in many  body colors other than black and white, including gray, pink, blue, and brown.

Labradorite displays a type of color play called schiller. The schiller effect is also seen in other feldspar rocks and gem stones including larvikite and moonstone. Blue and green effects are most common, but other colors are known.

Schiller is caused by microscopic thin layers or flakes within the structure of the stone.

Fire agate is another pretty rock/gem that displays a play of color phenomena. In this case the phenomena is called iridescence

Iridescence is usually caused by thin films of iron oxide or minute internal fractures.

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Industry News...

Tucson Gem Shows Are Here

The world series for colored gem stones is here!

I think there are more than forty different gem industry trade shows going on in Tucson over the next couple of weeks.

This truly is the year's main event for the gem industry. Dealers and buyers gather in Tucson, Arizona, each February to meet and greet, swap news, information, speculation, questions and rumors.

It's the one time of the year that we can get together to socialize... and do business.

This is where new discoveries are introduced to dealers, jewelry manufacturers and  retail jewelers.

If you're going to Tucson send me a note... maybe we can get together.

If you're not going, you can still view the Tucson Show Guide on-line.


I hope you noticed our new addition... ads in the right margin.

It's another small source of revenue for us (gotta keep those gem prices down) and possibly another resource for you. We're not sure who will be advertising, since we don't control that. I'm guessing on-line jewelry sales sites... and maybe even other gem dealers.

I hope the ads will be useful to you.

We'll be adding ads to many of our pages as we remodel and freshen our web site.


Jewelry Dealers

See you in Tucson!

Are you making up heart pendants, stud earrings and other jewelry for Valentine's Day customers? Now is the time! Talk it up, and make those sales.

Also, be sure to check out that great book called Make Your Content PREsell.


Jewelry Dealers Program

Do you enjoy jewelry and gems?

Do you enjoy talking with friends and co-workers?

Take a look at our great Jewelry Dealers Program.

Carolyn Doyle

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