A drusy is a tiny quartz crystal that is found inside, or on the surface of, another stone. Quartz is silicon dioxide, one of the most common elements on Earth. Quartz itself actually comprises almost 1/8 of the Earth's crust. Drusy quartz is much rarer, as it is found within larger quartz geodes. The extremely tiny drusy quartzes are used in jewelry. Quantity and quality of drusy quartz determines its value.
Finding Drusy Quartz in Nature
Miners and excavators sometimes come across small pockets concealed in deposits of other stones. These pockets contain spheres of crystal, called geodes. In fact, the name geode means "earth-like" in Greek, and accurately describes the spheres' appearance. Quartz geodes are thought to be formed in one of two ways, depending on the outer rock in which they are found. Those discovered in lava rock, specifically rhyolite, were formed when steam escaping from the hot lava created bubbles that later became hollow cavities. Later, water moved through the cavities depositing the minerals that became the quartz. In the case of quartz geodes found in sedimentary rock, the story is different. Water seeped through calcite deposits rich in lime. The water caused a chemical reaction that dissolved away mineral nodes and filled them with quartz crystals. Eventually, even the interior of these nodes were eaten away, and the empty spaces filled with sparkling drusy quartz.
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Drusy quartz looks a lot like sugar crystals. The individual stones vary widely in exact size and shape. Often the drusy quartzes are attached directly to the surfaces of larger pieces of quartz. Drusy quartz can be sparsely dispersed across the larger stone or deposited in quantity in specific spots. The more extensive and complete the coverage, the greater the value of the drusy quartz.
Jewelry Made From Drusy Quartz
Drusy quartz is increasingly popular as jewelry. Much of the world's supply comes from Brazil, where miners pilot holes into geode deposits. Only 1 in 1,000 actually contains the desired drusies. Further increasing the price is the fact that there is no way to tell if a geode is actually hollow except by hitting the outside of it with a metal bar. Cutters examine the drusy-covered stones to determine acceptability. Inferior pieces worth as little as $15 or $20 go to mass market dealers in China and India. On the other hand, the best pieces of drusy quartz can fetch as much as $200.
The tiny crystals are often further treated to enhance their desirability as articles of fashion. Drusy quartz can be dyed any number of colors. The crystals can also be coated with titanium to produce shimmering iridescent finishes. Drusies that are found attached to "luscious" orange, yellow and white stone command especially high prices. Buyers should seek out properly cut and set stones, and avoid mass market pieces that emphasize quantity over quality.