ROCK CRYSTAL, the clear and colorless variety of quartz
VARIETY OF: Quartz , SiO 2 , Silicon Dioxide .
USES: Ornamental stone and gemstone.
INDEX OF REFRACTION: 1.544-1.553
CRYSTAL SYSTEM: trigonal
Rock Crystal is the name given to all clear colorless quartz.
It is widely used as a popular ornamental stone and is also used as a
Although it is one of the least expensive gemstones, cut rock crystal
has been used as imitation diamonds.
Rock crystal lacks the fire, color (of course) and the rarity to be ranked as a fine precious gemstone.
None-the-less, rock crystal is in wide use as a gemstone due to its beauty, affordability,
availability, and ease of cutting.
The most common use for rock crystal is in ornamental carvings.
A well known ornamental carving for rock crystal is the crystal ball of fortune
While rock crystal is common it is hard to find large crystals
of quartz with the clarity and size required for the crystal balls
that most of us associate with fortune tellers. Rock crystal is
used for many ornamental carvings from spheres (crystal balls)
to pyramids to obelisks to figurines to eggs to bowls to wands.
There are also many fine chandeliers that are outfitted with rock
Rock crystal can have the colorless clarity of pure water, unlike ordinary
window glass which is a pale green. Yet the most common flaws - internal
fractures - result in veils and colorful refractions that lend beauty to an
otherwise ordinary object.
Rock crystal is an alternate and traditional
birthstone for the month of April. Quartz is often associated with
balance, clarity, and energy.
Many people prefer uncut clusters of rock crystal.
These natural treasures look like crystal cities of fantasy stories.
The long slender clear prisms of quartz projecting upward from a common
base are true mineralogical wonders that can be admired by all.
They cost of good clusters of rock crystal is quite affordable and comes
from sources around the world. The best rock crystal sources are in the
famous Hot Springs area of Arkansas, USA; Cumberland, England; St. Gotthard,
Switzerland; Brazil and Madagascar. Large individual crystals of quartz
have been found in Brazil, the largest weighs over 44 tons.
Rock crystal often has inclusions of other minerals and these inclusions
sometimes produce popular varieties of ornamental stone.
Golden rutile inclusions produce a unique stone aptly named
rutilated quartz that has a very hair-like look.
Another apply named stone is called tourmalinated quartz and
contains intricately crossing needles of black
trapped in the clear crystal.
Phantoms are a result of inclusions which occur when other minerals such as
or even milky quartz
form as a crust on the surface of the crystals during a hiatus in the crystal's
growth. The crystal then grows out and around the encrusting growth, encasing it
inside. But since the thin encrustations formed over a crystal complete
with crystal faces it appears that there is a crystal inside the crystal.
The encrustations are often incomplete or diffuse and appear ghostly,
hence the name phantom.
Rock crystal is only one of several quartz varieties.
Other varieties that form macroscopic (large enough to see) crystals
are as follows:
Amethyst is the purple gemstone variety.
Citrine is a yellow to orange gemstone variety that is rare in nature but is often created by heating Amethyst.
Milky Quartz is the cloudy white variety.
Prasiolite is the leek-green variety.
Rose quartz is a pink to reddish pink variety.
Smoky quartz is the brown to gray variety.