sand

Is it hard to believe that something as common as sand or dust is made of, basically, the same ingredients as the most beautiful amethyst?  Silica and oxygen are two of the most common elements on Earth, and they are the two needed to form quartz, a group of minerals which contains, among other gemstones, amethyst.  What a gift that, sometimes, the simplest and most common ingredients make an awe-inspiring product.

The “Quartz Family” is a wide-ranging group.  Amethyst is part of the large or single crystal strand of this group, along with citrine, smoky quartz, rock quartz (colorless quartz), and prasiolite (green quartz).  These are the quartz gemstones that are likely to be faceted in order to refract light.  They are more transparent, being cut from a single crystal.  There are two main reasons why these gemstones are different hues.  Trace elements such as iron can mingle with the silica and oxygen to influence the color.  Heat and/or irradiation acting on the mineral can also change its color.  Citrine, for example, is generally made by heat-treating pale amethyst.

Another branch of the quartz group is the microcrystalline strand.  Gemstones like tiger’s eye and aventurine are aggregates of many, many small quartz crystals.  These gemstones are generally translucent or opaque and are rarely faceted.  You might see them carved into cabochons or made into beads.  Colorless quartzite is an aggregate that is often dyed in various colors, sometimes to mimic other gemstones like jade.

Gemstones with cryptocrystalline structure have crystals too small to be seen without a powerful microscope.  Chalcedony, agate, and chrysoprase fall into this strand.  Chalcedony comes in various colors, both naturally and with man’s help.  Chrome chalcedony is naturally green due to a trace element of chromium.  But black onyx is actually chalcedony that has been dyed black.  Chrysoprase, one of the most valuable gemstones in the quartz group, is a translucent apple-green due to the presence of nickel.  These gemstones are sometimes faceted but usually are made into cabochons, beads or other carvings.  Agate, a multi-colored banded gemstone, can be used to carve cameos.

Quartz comes from almost every corner of the globe.  South America, North America, Australia, Africa, Asia, and even Europe all have deposits of quartz.  Because it’s so plentiful, even in large pieces, quartz is generally affordable.  We often think that the more expensive something is, the more beautiful it must be.  But that’s just not true in the case of quartz!

amethyst