Download April`s Mineral—Star Blue Quartz Alabama`s State Gemstone

Physical Properties of
Star Blue Quartz
Chemical Formula
Chemical
Classification
Cleavage
Color
Crystal System
Crystal Forms and
Aggregates
Fracture
Luster
Mohs Hardness
Specific Gravity
Streak
Transparency
Tenacity
SiO2
Silicon Dioxide
Indiscernible. Seldom exhibits
parting.
Colorless, white, purple, pink,
brown, and black. Also gray, green,
orange, yellow, blue, and red.
Sometimes multicolored or
banded.
Hexagonal
Crystals, which are hexagonal in
shape, vary in shape and size.
Quartz crystals are unique and very
identifiable with their pointed and
often uneven terminations. Crystals
can be in enormous prismatic and
stubby crystals, or in pointed
aggregates of such crystals. Crystals
are usually striated horizontally,
and are sometimes doubly
terminated. Quartz crystal habits
include drusy, grainy, bladed, as
linings of geodes, as rounded
waterworn pebbles, radiating, as
pointy pyramids on a matrix, as
dense agglomerations of small
crystals, massive, globular,
stalactitic, crusty, in nodules, and in
amygdules.
Conchoidal
Vitreous. Transparent, colorless
Quartz crystals from a few distinct
localities may be adamantine.
7
2.6—2.7
White
Transparent to opaque
Brittle
April’s Mineral—Star Blue Quartz
Alabama’s State Gemstone
Quartz is an abundant mineral in Alabama rocks.
Several varieties of quartz are valuable as
gemstones, including the popular amethyst variety.
Alabama's state gem is the Star Blue Quartz, (SiO2,)
Silicon dioxide. It is one of the most beautiful
gemstones on earth, and the cheapest because
there are so many. There are also other states with
quartz. With the approval of a bill proposed by
Senator Don Hale, Cullman County, the star blue
quartz was named the official gemstone for the State
of Alabama by Act no. 90-203 in 1990.
Most quartz is a souvenir of volcanoes, which melt
silica, which is then carried by water into crevices,
where it crystallizes. Such quartz often includes
traces of other minerals picked up by water flowing
underground.
Crystalline form of silica SiO2, one of the most
abundant minerals of the Earth's crust (12% by
volume). Quartz occurs in many different kinds of
rock, including sandstone and granite. It ranks 7 on
the Mohs scale of hardness and is resistant to
chemical or mechanical breakdown. Quartzes vary
according to the size and purity of their crystals.
Crystals of pure quartz are coarse, colourless,
transparent, show no cleavage, and fracture
unevenly; this form is usually called rock crystal.
Impure colored varieties, often used as gemstones,
include agate, citrine quartz, and amethyst. Quartz is
also used as a general name for the cryptocrystalline
and noncrystalline varieties of silica, such as
chalcedony, chert, and opal.
There is different colored quartz. New Hampshire
has smokey, South Dakota rose, Arkansas and
Georgia star blue. Quartz is made into glass,
eyeglasses, electrical components, abrasives, and
gemstone and building stone.
Some forms of Quartz, especially the gemstone
forms, have their color enhanced. There is a
transparent sky blue form of Quartz crystals, as well
as a wildly iridescent type that are synthetically
colored by irradiation of gold. In some localities,
Hematite forms a thin red or brown layer internally in
the Quartz crystal, giving it a natural bright red to
brown coloring, and sometimes even a mild natural
iridescence.