Quartz


Quartz

Rose quartz

Amethyst

Quartz is silicon dioxide, SiO2. Quartz is abundant in the Earth's crust, being the chemically simplest form of the silicates. It appears in many forms. All the samples here are displayed in the Smithsonian Museum of Natural History.

This section of agate quartz is displayed at about actual size.

Quartz is typically characterized by a density of about 2.65 gm/cm3, an index of refraction of about 1.54-1.55, and a hardness of about 7 on the Mohs hardness scale.

Giant quartz crystals
Quartz with other minerals
Milky quartz
Gwendel quartz

Clear crystal quartz forms naturally when silica rich solutions occur in underground cavities and fractures where conditions will allow unobstructed growth. The smooth planar surfaces reflect the symmetry of the crystal lattice, but do not represent cleavage planes. When the hexagonal symmetry is exhibited by the crystals, it represents the pattern formed by unobstructed growth.


Smoky Quartz

Citrine Quartz

Ametrine Quartz

Clear Quartz

Agate Quartz

Chalcedony Quartz

Jasper Quartz

Onyx Quartz

Sardonyx Quartz

Bloodstone Quartz

Chrysoprase Quartz

Flint Quartz
Minerals
Selection of common minerals
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Rose Quartz

Quartz is silicon dioxide, SiO2. Quartz is abundant in the Earth's crust, being the chemically simplest form of the silicates. All the samples here are displayed in the Smithsonian Museum of Natural History. The rose quartz sample at right is about 18x10 cm and is from Minas Gerais, Brazil.


A sample of rose quartz on display at the Smithsonian Museum of Natural History

The gems above are 84 and 110.6 carats and are from Minas Gerais, Brazil.

This rose quartz gem is 374.9 carats, also from Minas Gerais.

This sample of rose quartz is about 22x15 cm and is from Galilea mine, Sapucaia pegmatite, Minas Gerais, Brazil.

"This specimen is sometimes called the "Pink Tutu" because of its rose quartz frill. The smoky quartz formed first, then the rose quartz. Geologists suspect the pink tint comes from traces of alumninum and phosphorus."

This shows more detail about the habit of formation of the sample above. Below is another view of this extraordinary specimen.

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