Inclusions & Varieties

Quartz is a mineral of many names, which can be confusing, but helps to identify the variety easier than using the technical name for all samples.  There are varieties of quartz that are crystalline and varieties of quartz that are cryptocrystalline, or massive.  We will explain the difference between the two sub categories.

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Crystalline quartz are your typical crystals that you would see in a collection or for sale.  Your standard “rock crystal” refers to colorless crystals, “milky quartz” is used for crystals with white crystals.  Smoky quartz is brown to black, color due to natural radiation in the area they developed.  Some smoky quartz is colored by artificial exposure to radiation, to make a more desirable and saleable product.  It should also be noted that the correct use is “smoky” not, “smokey”. Citrine is an uncommon color in nature, with various shades of yellow inside the crystal.   Amethyst is quartz with purple color, caused by inclusions of iron during the growth.  Millions of amethyst clusters from Brazil have been heated to convert the color from purple to an orange/red/yellow hue, commonly found for sale at gift shops around the world.    17810_02Rose quartz is usually found as massive material, in fact, several mountains around the world are made out of rose quartz.  It is much more uncommon to find them as crystals.  Typically, rose quartz crystals are rather small, sometimes people confuse polished rose quartz as natural crystals.

 

In addition to these basic varieties of quartz, the crystals can also host a wide variety of inclusions.  It could almost be said that a majority of minerals in the world can be found along with quartz and often included inside.  Popular examples of this are rutilated quartz, found all over the world.  Rutile is a simple mineral, TiO2, which is nearly the same as Quartz, SiO2, so if there is Titanium and Silicon in the growing atmosphere, you have a strong chance of rutilated quartz. 15572_02 Rutile can take on many colors and forms, from thin needles of red, yellow and gold to big blades of bright golden color, sometimes radiating in a star pattern from a center of metallic hematite.  Red quartz is very popular, the color of which is caused by inclusions of hematite dispersed throughout the crystal.  Tourmaline is commonly found included in quartz, giving a possibility of a rainbow of colors included, though most often, black.  Green quartz crystals are prized, the best color coming from inclusions of hedenbergite, a rock forming mineral.

Beyond the crystallized quartz, you have a whole other side to quartz, the massive, or Cryptocrystalline variety.  This is the area where Quartz is often found to be the most confusing to new collectors.  Under the various names, Agate, Jasper, Chalcedony, Carnelian, Opal, the common uniting factor is that they are all quartz.  All of these terms are simply describing factors to the hunk of quartz.

AGATE Cabochon from Indonesia

Agate is used to describe massive quartz with color that, when cut into think sections, will allow light to pass through.

Jasper is the exact same material, however, light will not pass through a slab of jasper, as jasper is quartz filled with solid inclusions.

Carnelian, Chrysoprase and hundreds, if not thousands of trade names are given to agates with various colors or common traits.  For instance, most any agate with orange coloring is going to be called Carnelian.  While Chyrsoprase is typically reserved for agate with nickel, often, any green agate is labeled with this name.  Some names give an idea of what is inside the agate, like Moss, and sometimes they are named after a location, like Horse Canyon Agate, which is mossy.

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