By Hannah Dahl
February in Tucson is synonymous with gem shows. During the next few weeks, thousands of people flock here to participate in the world’s largest gem and mineral show. World-renowned dealers and gemologists display eye-catching crystals and dazzling gemstones in venues throughout the city.
While all the glitz and glamour is exciting, gem shows are more than “sparkly rocks.” Prepare yourself for this year’s shows by brushing up on the basics of mineralogy. Having a basic background of science under your belt will make the entire experience richer and more meaningful, and can help you make more informed decisions while shopping for gems.
Animal, vegetable, mineral?
Before visiting your first show, you’ll want to have a good grasp on basic terminology. Minerals, crystals and gemstones are not the same thing, though sometimes the terms are used interchangeably.
A mineral is a material formed in a specific structure from elements in the periodic table, says Eric Fritz, the North American manager for the Gemological Association of Great Britain, the world’s oldest gemological educational organization.
Think of a mineral as the base ingredient or building block, from which endless possibilities of formations can be created. The specific way the elements are arranged determines what shape, color and size the mineral will take on, he says.
These forms start out at the atomic level and build on each other, repeating the structure to create minerals such as mica and gypsum. This process of repeating is how crystals are formed.
“All crystals are minerals, but not all minerals are crystals,” says Mike Davis, owner of Dah Rock Shop, a gem and mineral retailer that has been in Tucson for 45 years.
Most crystals are formed from a single element, such as diamonds, which come from the carbon atom, Fritz says. However, if multiple minerals bond together, then a rock is formed. Rocks generally contain a mix of elements and don’t follow a specific structural pattern in the same way that crystals do.
Gemstones fall under another category entirely. A gemstone is a mineral that has been shaped, cut, polished or corrected by a human, Fritz says. These are generally used for art and jewelry.
In other words, your diamond ring could’ve started out as the element carbon, and then became a mineral, which then formed into a crystal structure, where it was harvested, cut and polished to become the beautiful gemstone that now sits on your ring finger.
Though gemstones and crystals have smooth surfaces, crystals found in nature tend to be larger than gemstones and have very distinctive shapes because they haven’t been altered by man, Fritz says. Rather than being polished by a machine, the flat sides of a naturally found crystal represent the outermost edges of the crystal’s growth.
Crystals are most often found growing underground, though on the rare occasion they can be found aboveground. Variations in the temperature and climate influence what form and color the crystals will take on, Davis says.
There are seven different forms of crystals, classified mainly by the number of sides each crystal has, Fritz explains. These range from cubic (the simplest form) to monoclinic (a complex mix of prisms and parallelograms).
The Tucson Gem and Mineral Society has announced crystals and crystal forms are the theme for the 2018 shows, so there are sure to be plenty of spectacular mineral clusters on display during the next few weeks. But how do you tell if what you’re looking at is a real crystal or not?
According to Davis, if the crystal looks “too perfect” or doesn’t seem to have any imperfections that could be a warning sign. Because crystals occur naturally, they usually have some blemishes or irregularities. While naturally pure crystals do exist, they are rare and likely to come with a high price tag, Davis says.
Davis recommends asking the dealers if you have questions about the authenticity of a particular crystal, or shopping around at different venues to compare similar forms of the same crystal before picking one to buy.
For a complete list of gem shows, visit tucsongemshows.net/coming.html
