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The World of Quartz Gemstones

Natural Lemon Quartz
Natural Lemon Quartz Gemstone

Quartz is the second most common mineral on earth, making up about 12% of the Earth's crust. Only feldspar is more common. However, one shouldn't conclude from this that quartz gemstones are uninteresting. In fact the quartz family is surprisingly diverse. The fact that quartz is inexpensive just means there are more opportunities for collectors.

Buy Natural Amethyst Gems from GemSelect
Natural Amethyst from GemSelect

All quartz is silicon dioxide, but this was not discovered until the early nineteenth century. Prior to that, many different forms of quartz were thought to be distinct minerals.

This is not really surprising, since there are two very different branches of the quartz family. When most people think of quartz, they think of what is known as macrocrystalline quartz, which includes rock crystal, amethyst, citrine, smoky quartz, rose quartz and tiger's eye. Macrocrystalline quartz, as the name suggests, has large crystals that can be distinguished by the naked eye. This type of quartz is mainly transparent to translucent, with a vitreous luster.

Chalcedony Gems at GemSelect
Chalcedony from GemSelect

The other type of quartz is known as cryptocrystalline quartz. It has microscopically (or submicroscopically) small crystals and is usually translucent to opaque, with a waxy to greasy or dull luster. This kind of quartz has fibrous and granular subcategories. The fibrous varieties are known as chalcedony, but this name covers a remarkable variety of stones.

Natural Onyx

In practice, the name chalcedony refers to solid colored cryptocrystalline quartz, especially of a light color. The patterned varieties tend to have their own names. The most famous of these include agate, distinguished by its bands of color; onyx, which is black and white layered chalcedony (and is usually dyed to produce a uniform black); carnelian, a yellow-orange to reddish-orange type of chalcedony, colored by iron; and chrysoprase, an apple-green variety that is colored by nickle.

Buy Jasper from GemSelect
Jasper Gemstone

The granular varieties include jasper and bloodstone. Jasper is typically multicolored, spotted or flamed. Especially treasured pieces form patterns that look like natural landscapes. Bloodstone, also known as heliotrope, is dark-green with flecks of red, caused by iron oxide.

Natural Agate at GemSelectThe diversity of many of these quartz varieties is remarkable. Agate, for example, has more than a dozen different types, many of them much sought after by collectors. They have quaint names like eye agate, which forms ring shapes with a point in the center; moss agate, distinguished by its moss-like patterns; and fire agate, which displays an unusual iridescence.

  • Prima Pubblicazione: February-27-2008
  • Ultima modifica: November-05-2019
  • © 2005-2021 GemSelect.com Tutti i diritti riservati.
    Qualsiasi riproduzione (testi o immagini) è strettamente proibita senza esplicita autorizzazione scritta da parte di GemSelect.com (SETT Company Ltd.).
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Dimensioni e peso

Gems are always measured in Millimeter (mm)

Dimensions are given as;
length x width x depth,
except for round stones which are;
diameter x depth

Select gems by size, not by weight!
Gem varieties vary in density, so carat weight is not a good indication of size

Note: 1ct = 0.2g

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