Information about and things made of or with Smoke Quartz

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PHYSICAL PROPERTIES:
VARIETY OF: Quartz , SiO 2 , Silicon Dioxide.
CRYSTAL SYSTEM: Hexagonal-Rhombohedral
COLOR: various shades of pink to a rosy-red.
USES: Gemstone and ornamental stone.
REFRACTIVE INDEX : 1.544-1.553
HARDNESS: 7
CLASS: tectosilicate
CLEAVAGE: none
FRACTURE: conchoidal
LUSTER: vitreous
STREAK: white
PLEOCHROISM: weak to distinct
SPECIFIC GRAVITY: 2.65
TRANSPARENCY: opaque to translucent, rarely transparent

PHYSICAL CHARACTERISTICS:
The Colors of Smoke Quartz range from tan, brown to light gray. These colors are
somewhat rare in the mineral world, Only a few other brown or black minerals are
ever cut for gemstones such as the smoky topaz, the very rare black beryl or the
brown corundum.

Phantom quartz shapes are sometimes present in the interior of quartz crystals, outlining
an earlier stage of the crystal's formation. These phantoms are usually composed of other minerals such as chlorite or other varieties of quartz This leaves a coating on most or all
of the surfaces of the crystal during its growth. The crystal then resumes its crystallization creating a phantom crystal outline within itself.

Smoky quartz commonly occurs in quartz veins where it crystallizes inside rock cavities known as vugs. It also is common in vugs or pockets in pegmatite dikes. Smoky quartz can occur as secondary quartz crystals on cryptocrystalline quartz like agate. These are known as Druzy Quartz It may form in cavities that form geodes.

The characteristic color of smoky quartz occurs in nature when rock crystal quartz is exposed to natural radiation from radioactive elements or adjacent radioactive rocks over long periods of time. We Know this because exposure of transparent quartz to radiation can alter the oxidation states of impurities in the quartz structure. Resulting in the characteristic colors of smoky quartz. Subsequent heating reverses this process.

Natural Smoke Quartz tends to be smoky to the base, whereas irradiated tends to have a
white crystal base next to the matrix rock. Also if it is so black you can not see through it
and it has good surface luster. It is probably irradiated. Natural Smoke Quartz crystals are
also a product of irradiation, but by nature in it's own very slow processes.

Smoky quartz often has minute cavity inclusions containing carbon dioxide or water. If there
is a sufficient number of these minute fluid inclusions then the quartz becomes opaque and is called milky quartz. Most smoky quartz forms on a matrix of milky quartz and crystals of smoky quartz often grade into milky quartz towards their base.

Often these cavities contain both liquid and gas these inclusions are known as enhydros. In
rare cases these inclusions can be visible to the naked eye and may show actual movement
of the gas through the liquid.

Smoky quartz sometimes forms with an etched pattern of lines, depressions and raised termination's. If these etched termination's are accompanied by plainly visible internal
cavities arranged in geometric patterns related to the quartz crystal structure, the form is referred to as skeletal or 'elestial' quartz. The internal cavities of skeletal quartz often
contain clay minerals of varied colors, sometimes accompanied by carbon dioxide or water. These cavities can have a layered or ribbed aspect and are sometimes so pronounced as to make the crystal almost hollow, giving rise to the term skeletal quartz.

Many different minerals can form as inclusions within smoky quartz. Some of the more important varieties of included quartz for gem use are rutilated quartz and tourmalinated
quartz. Some other common mineral inclusions in smoky quartz are chlorite, goethite and hematite.

LOCALITIES:
Some older locations like the Cairngorm Mountains in Scotland or Morion a very dark black opaque smoky quartz. Almost denote a variety of Smoke Quartz rather than a location. Then there are common names like Coon tail quartz which is a Smoke Quartz with alternating black and gray bands.

A few Other more noteworthy locations include Brazil, the worlds largest supplier. Pikes Peak area of Colorado. Here it is associated with green amazonite and the Swiss Alps, which have produced many tons of fine specimens.

The State of Montana is also producing some very nice specimens. Not to mention many other states in the US. Including our state of Idaho. Some very nice specimens of Topaz and Smoke Quarts also come from Alabaschka, near Mursinka, Ural Mountains, Russia.

All in all, Smoke Quartz is quite abundant. Which accounts for it's lower value as a gemstone. But nice mineral specimens are a different story.

COLLECTING LOCALITIES:
Crystal Park This locality is located SW of Butte, or NW of Dillon, high in the mountains. Access is easy on a good paved road, south from Wise River, or a gravel road from the south (west of Dillon). It is generally accessible only in the summer due to snow cover. Very fine specimens of quartz light amethyst and partially smoky, especially amethyst scepters can be collected. Single crystals of colorless quartz are often abundant, but the better amethyst scepters are uncommon. The locality has been upgraded to a maintained recreation site by
the Forest Service and includes a large parking area, toilet, paved trail with wheel chair
access, and other improvements. To collect, it is necessary to dig in a decomposed quartz monzonite with a shovel. Crystals can be found from the surface on down, but the best crystal "cavities" are encountered from about four feet on down. This area has been very popular in the last decade and finding fresh, ground is difficult. Yet, many fine specimens are recovered each year.

The area that is now Butte Montana rests on the southwestern side of a large mass of
granite, or quartz monzonite, that extends from the Highland Mountains northward about
70 miles, nearly to Helena. This rock formation, called the Boulder batholith. It dates to the Cretaceous era, about 70 to 80 million years ago. The Boulder batholith, especially the area south to east of Butte has many pegmatites with cavities that have produced spectacular specimens of smoky quartz, amethyst, amethyst overgrowths (including scepters) on smoky quartz, microcline, schorl, microcline and epidote. It is necessary to walk over a lot of forested ground looking for indications of a collapsed crystal pocket in a pegmatite to find that occasional spectacular crystal cavity. Some very fine specimens have been collected in recent years.

FACTS & USES:
If a Smoke Quartz contains rutilations, it is sometimes called Smoky Sagenite rather than Rutilated Quartz. Smoke Quartz has been misleadingly sold as Smoky Topaz. Smoke Quartz
is now often cooked at high temperatures to produce the more profitable orange yellow
Citrine. This process usually creates darker brownish orange stones. Which can be confused with the deeper color natural Citrine from Brazil.

Smoky quartz is also popular as an ornamental stone for jewelry and is carved into spheres, pyramids, obelisks, eggs, figurines and ornate statues.

The astrological signs of smoky quartz are Capricorn and Sagittarius.