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Single Citrine Crystal
SILICATES; TECTOSILICATES; SILICA GROUP · HEXAGONAL

Citrine

SiO2

Hardness
7
Streak
White
Spec. Gravity
2.6–2.7
System
Hexagonal
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About

Citrine is the yellow to brownish-red variety of  the mineral Quartz. It is a widely used as a gemstone, and after Amethyst it is the most popular Quartz gem. Most Citrine is formed by heat treating purple Amethyst. Citrine may also be produced by heat-treating Smoky Quartz from certain localities. In some Amethyst deposits, the Amethyst has been partially or fully changed over to yellow Citrine by natural means of heating.

Natural Citrine, which is rare, is yellow to orange-yellow, and occurs in much lighter hues than the heat-treated material, which is dark orange-brown to reddish-brown. Virtually all heat-treated material has a reddish tint, whereas the natural specimens do not. Natural light yellow Citrine is often called "Lemon Quartz" on the gemstone market. Sometimes Citrine has a "smoky" hue to it, and can be borderlined between Citrine and Smoky Quartz, with either definition being correct.

For additional information, see the gemstone section on Citrine.

Crystal Forms & Aggregates

Most often as protruding clusters of pyramids on a geode base. Also occurs as short, stubby, terminated crystals, either singular or in drusy aggregates, and occasionally as long prismatic crystals and groupings. Also occurs massive and crusty.

Complex Tests

Striking Features

Color and crystal habits

Environment

Varieties

✓ common  · ✗ uncommon

  • Ametrine— Mixture of Amethyst and Citrine. It is partially purple and partially yellow or orange, with the color zones often sharply divided. More information can be found on the Ametrine gemstone page.
  • Cactus Quartz— Form of Quartz, usually Amethyst, Citrine, or a combination of the two, that contains a large crystal or crystals overgrown with a layer of spiky smaller crystals. Cactus Quartz is specific to Boekenhouthoek (Magaliesberg) in South Africa.
  • Lemon Quartz— Form of naturally colored light yellow Citrine. It is distinguished from most Citrine by lacking orange, brown, or reddish tints.

Uses

Citrine is known mainly for its use as a gemstone. Gems are faceted for jewelry, and it is often used as an inexpensive substitute for Topaz. Citrine is also popular among mineral collectors, and small pieces and drusy plates are often sold to amateur collectors in gift shops.

Noteworthy Localities

Natural Citrine is not common and occurs sparingly in many large Quartz deposits. Most commercial gem-grade material comes from Rio Grande do Sul and Minas Gerais, Brazil, but almost all of the Brazilian material is heat treated Amethyst.

A classic exhausted locality for natural Citrine is Olkhovka in the Northern Ural Mountains, Russia. Other locations where natural Citrine is found is San Cristobal, Santander, Colombia; Lubumbashi in Katanga (Shaba), Congo (Zaire); Antananarivo Province, Madagascar; Salamanca, Spain; and Dauphine, France. In Boekenhoutshoek (Magaliesberg), Mkobola district, South Africa, a unique form of natural Citrine is found together with Amethyst that has a spiky overgrowth of small crystals popularly called "Cactus Quartz".

Common Mineral Associations

Distinguishing Similar Minerals

Topaz - Harder (8), has perfect cleavage, different crystal formation.
Chrysoberyl - Harder (8½), different crystal formation.
Apatite - Softer (5), crystal terminations usually differ from Citrine.
Fluorite - Much softer (4), different crystal formation.
Heliodor (Beryl) - Harder (7½ - 8), crystals are usually different (more elongated and perfect hexagons).

Photos

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Crystal forms

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Prismatic Bipyramidal
Complex Bipyramidal
Modified Prismatic Bipyramidal
Complex Prismatic