The Major Varieties of Quartz (Photos)

Quartz is the most common mineral on the face of the Earth. It is found in nearly every geological environment and is at least a component of almost every rock type. It frequently is the primary mineral, >98%. It is also the most varied in terms of varieties, colors and forms.

There are many different varieties of quartz, several of which are semi-precious gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Europe and the Middle East.

The Major Varieties of Quartz

Some macrocrystalline (large crystal) varieties are well known and popular as ornamental stone and as gemstones.

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 a leek-green gemstone variety that is rare in nature but is created by heating Amethyst from certain locations.
Rose quartz is a pink to reddish pink variety.
Smoky quartz is the brown to gray variety.

Cryptocrystalline (crystals too small to be seen even by a microscope) varieties are also used as semi-precious stones and for ornamental purposes. These varieties are divided more by character than by color.

The primary varieties of chalcedony are as follows:

Agate is a banded variety (sometimes with translucent bands)
Bloodstone is green with red speckles
Carnelian is yellow to orange
Chrysoprase is green
Flint is generally black with a fibrous microscopic structure
Jasper is any colorful agate
Onyx is black, white, or alternating black and white
Sard is yellow to brown
Sardonyx is banded, alternating sard and (usually white) onyx

The primary varieties of quartz

Agate

Agate Multi-colored, banded chalcedony, semi-translucent to translucen. Although agates may be found in various kinds of rock, they are classically associated with volcanic rocks and can be common in certain metamorphic rocks.

Onyx

onyx contain bands of black and/or white.
Copyright © Rob Lavinsky

Onyx Agate where the bands are straight, parallel and consistent in size. A typical onyx consists of two or more black and white strata.

Jasper

Rough of Kaleidoscope Jasper from Oregon

Jasper Opaque cryptocrystalline quartz, typically red to brow. The common red color is due to iron(III) inclusions. The mineral aggregate breaks with a smooth surface and is used for ornamentation or as a gemstone.

Tiger's eye

Polished tiger's eye gemstone

Tiger's eye is a chatoyant gemstone that is usually a metamorphic rock with a golden to red-brown color and a silky lustre. As members of the quartz group, tiger's eye and the related blue-colored mineral hawk's eye gain their silky, lustrous appearance from the parallel intergrowth of quartz crystals and altered amphibole fibers that have mostly turned into limonite. It is a classic example of pseudomorphous replacement by silica of fibrous crocidolite (blue asbestos). An incompletely silicified blue variant is known as hawk's eye.

Aventurine

Aventurine is used for a number of applications,
including landscape stone, building stone, aquaria, monuments, and jewelry.

Aventurine translucent chalcedony with small inclusions (usually mica) that shimmer. The most common colour of aventurine is green, but it may also be orange, brown, yellow, blue, or gray. Chrome-bearing fuchsite (a variety of muscovite mica) is the classic inclusion, and gives a silvery green or blue sheen.

Amethyst

Amethyst
Photo by @luminous.element

Amethyst is the purple variety of quartz and is a popular gemstone. Amethyst is a semiprecious stone and is the traditional birthstone for February.

Rutilated quartz

Varieties of Quartz Quartz with Rutile inclusions from

Quartz with Rutile inclusions from
Novo Horizonte, Bahia, Northeast Region, Brazil
Copyright © Rob Lavinsky

Rutilated quartz is a type of quartz that contains acicular (needle-like) inclusions of rutile. It is used for gemstones. These inclusions mostly look golden, but they also can look silver, copper red or deep black. They can be distributed randomly or in bundles, which sometimes are arranged star-like, and they can be sparse or dense enough to make the quartz body nearly opaque. While otherwise inclusions often reduce the value of a crystal, rutilated quartz is valued for the quality and beauty of these inclusions.

Citrine

Giant Citrine faceted gem from Minas Gerais, Brazil.

Citrine is a variety of quartz whose color ranges from a pale yellow to brown due to ferric impurities. Natural citrines are rare; most commercial citrines are heat-treated amethysts or smoky quartzes.

Prasiolite

Raw natural prasiolite

Prasiolite (or vermarine) is the name for any quartz crystal or cluster that is green in color. It is a rare stone in nature; artificially produced Prasiolite is heat treated amethyst.

Rose quartz

Rose quartz Pink, translucent, may display diasteris. The color is usually considered as due to trace amounts of titanium, iron, or manganese, in the massive material.

Milky Quartz

Milky Quartz Cluster

Milky Quartz is any quartz crystal or cluster that is white in color and cloudy. The cloudy white character of the crystals is what lead to the variety name, milky. Milky quartz is the most common variety of crystalline quartz. The white color is caused by minute fluid inclusions of gas, liquid, or both, trapped during crystal formation, making it of little value for optical and quality gemstone applications

Smoky quartz

Smoky quartz is the brown to black, and sometimes smoky gray version of quartz. It ranges in clarity from almost complete transparency to a brownish-gray crystal that is almost opaque. Smoky quartz, a variety itself of quartz, has a few varieties of its own. Read about it here.

Carnelian

Polished Carnelian

Carnelian Reddish orange chalcedony, translucen. The color can vary greatly, ranging from pale orange to an intense almost-black coloration. Similar to carnelian is sard, which is generally harder and darker.

Chalcedony

vChalcedony is a cryptocrystalline quartz and moganite mixture. The term is generally only used for white or lightly colored material. Otherwise more specific names are used. Chalcedony has a waxy luster, and may be semitransparent or translucent. It can assume a wide range of colors, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black.

Mtorolite

Mtorolite zimbabwe

Mtorolite is a green variety of chalcedony, which has been colored by chromium. Also known as chrome chalcedony, it is principally found in Zimbabwe.

Chrysoprase

(chrysoprase). An amazing new find from Australia.
Photo by: Australian Outback Mining

Chrysoprase is a green variety of chalcedony, which has been colored by nickel oxide. Its color is normally apple-green, but varies to deep green. Chrysoprase is cryptocrystalline, which means that it is composed of crystals so fine that they cannot be seen as distinct particles under normal magnification.