Staff member
Jun 3, 2020
Quartz is a hard, crystalline mineral composed of Silicon and Oxygen atoms. It is the most abundant mineral found at the earth's surface, and it's unique properties make it useful in several industries.

Distribution of Quartz
Quartz is the most abundant mineral on Earth's surface. It is found in all types of rocks, formed at all temperatures, and widely distributed in all parts of the world. It is resistant to both physical and chemical weathering, which makes it the dominant mineral in mountain tops and weathered remains of rocks. It is also the primary constituent of beach, river and desert sand. The mineable deposits can be found throughout the world.

Physical properties of Quartz
S. No.PropertyValue
1Chemical ClassificationSilicate
2ColorQuartz occurs in virtually every color. Common colors are clear, white, gray, purple, yellow, brown, black, pink, green, red.
3StreakColorless (harder than the streak plate)
5DiaphaneityTransparent to translucent
6CleavageNone - typically breaks with a conchoidal fracture
7Mohs Hardness7
8Specific Gravity2.6 to 2.7
9Diagnostic PropertiesConchoidal fracture, glassy luster, hardness
10Chemical CompositionSiO2
11Crystal SystemHexagonal
12UsesGlass making, abrasive, foundry sand, hydraulic fracturing proppant, gemstones

Uses of Quartz
Quartz is one of the most useful naturally occurring substances due to its unique physical and chemical properties. It is very durable due to its high hardness (7). It is also chemically inert in contact with most substances. It is useful in electronic products due to its electrical resistance and heat resistance. Some varieties of Quartz are also used as gemstones due to their luster, color and durability.

Major varieties of Quartz
The major varieties of Quartz according to their microstructure are listed below:
TypeColor & DescriptionTransparency
Herkimer diamondColorlessTransparent
Rock crystalColorlessTransparent
AmethystPurple to violet colored quartzTransparent
CitrineYellow quartz ranging to reddish orange or brown, and occasionally greenish yellowTransparent
AmetrineA mix of amethyst and citrine with hues of purple/violet and yellow or orange/brownTransparent
Rose quartzPink, may display diasterismTransparent
ChalcedonyFibrous, variously translucent, cryptocrystalline quartz occurring in many varieties.
The term is often used for white, cloudy, or lightly colored material intergrown with moganite.
Otherwise more specific names are used.
CarnelianReddish orange chalcedonyTranslucent
AventurineQuartz with tiny aligned inclusions (usually mica) that shimmer with aventurescenceTranslucent to opaque
AgateMulti-colored, curved or concentric banded chalcedony (cf. Onyx)Semi-translucent to translucent
OnyxMulti-colored, straight banded chalcedony or chert (cf. Agate)Semi-translucent to opaque
JasperOpaque cryptocrystalline quartz, typically red to brown but often used for other colorsOpaque
Milky quartzWhite, may display diasterismTranslucent to opaque
Smoky quartzLight to dark gray, sometimes with a brownish hueTranslucent to opaque
Tiger's eyeFibrous gold, red-brown or bluish colored chalcedony, exhibiting chatoyancy.
PrasioliteMint greenTransparent
Rutilated quartzContains acicular (needle-like) inclusions of rutile
Dumortierite quartzContains large amounts of dumortierite crystalsBlue

Synthetic Quartz crystals
Although Quartz is abundant on earth's surface, the demand grew consistently for high-quality crystals with specific properties. This lead to the process of growing synthetic quartz crystals for use in optical and electronic equipments. The cost of growing synthetic quartz crystals is on par with mining, and involves the development of crystals at high temperatures from silica rich waters. The crystals can be developed in specific size, shape and colors depending on the requirements.


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