Amethyst

Real mineral · common · SiO₂

A variety of quartz coloured by iron impurities and natural irradiation. Typically found lining the cavities of volcanic basalt geodes. Heat treatment above 400°C converts it to yellow citrine.

Identity

Formula

SiO₂

Chemical class

silicate

Mineral group

Bloodstone, Carnelian, Chalcedony, Citrine, Quartz, Rose Quartz, Smoky Quartz, Tiger's Eye

Also known as

Purple quartz, Violet quartz

Crystallography

Crystal system

trigonal

Habits

prismatic, drusy

Fracture

conchoidal

Physical properties

Mohs hardness

7

Density

2.65 g/cm³

Luster

vitreous

Colors

purple, violet, pale purple, deep purple

Streak

white

Transparency

transparent, translucent

Geology

Origins

hydrothermal, igneous

Host rocks

basalt, granite, geodes

Associated minerals

Calcite, Quartz, Goethite

Geography

Brazil, Uruguay, Zambia, Russia, South Korea

Classification

Rarity

common

Gem quality

Yes

Arcane properties

Affinity

arcane, mind

Effects

mind, warding

Planar origin

Material Plane

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