Provenite

About Citrine

SiO₂

The yellow to yellow-orange (sometimes yellow-green) variety of quartz, with weak dichroism in polarized light. The cause of colour in natural citrine is still debated; aluminium-based colour centres created by irradiation, related to those in smoky quartz, are the leading explanation, and this accounts for smoky phantoms and 'smoky citrine'. Natural citrine is very rare and is usually paler, often with a slightly smoky tone. Most citrine on the market is heat-treated amethyst (or heated smoky quartz); its colour comes from fine iron oxides such as hematite and goethite, it shows no dichroism, and strictly it is not citrine. Colour zoning, deepest at crystal tips in geodes, points to heated amethyst. Bicoloured amethyst-citrine (ametrine) from Bolivia is a natural example of citrine sectors.

Show 11 localities on the map

Photos of Citrine

Sparkling orange-yellow citrine-coloured quartz specimen from Boekenhoutshoek, 9.1 cm.
Citrine · Boekenhoutshoek (Boekenhouthoek)
Sparkling orange-yellow citrine-coloured quartz specimen from Boekenhoutshoek, 9.1 cm.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Small-cabinet citrine specimen from the Esmeralda Mine, Mesa Grande District, 8.5 cm.
Citrine · Esmeralda Mine
Small-cabinet citrine specimen from the Esmeralda Mine, Mesa Grande District, 8.5 cm.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Amber-coloured citrine crystal knob from Charcas, San Luis Potosí, 6.5 cm.
Citrine · Charcas
Amber-coloured citrine crystal knob from Charcas, San Luis Potosí, 6.5 cm.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Etched, elongated ametrine crystal (amethyst with yellow citrine hues) from the Anahi Mine, 12.7 cm long.
Citrine · Anahi Mine
Etched, elongated ametrine crystal (amethyst with yellow citrine hues) from the Anahi Mine, 12.7 cm long.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Transparent amber-coloured citrine crystals from the Araçuaí area, Minas Gerais.
Citrine · Araçuaí
Transparent amber-coloured citrine crystals from the Araçuaí area, Minas Gerais.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Smoky quartz sceptre on a citrine-coloured shaft from the Goboboseb Mountains, 9.2 cm.
Citrine · Goboboseb Mountains
Smoky quartz sceptre on a citrine-coloured shaft from the Goboboseb Mountains, 9.2 cm.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Single sharp, glassy citrine crystal from Hiddenite, North Carolina, 6.5 cm.
Citrine · Hiddenite (Alexander County)
Single sharp, glassy citrine crystal from Hiddenite, North Carolina, 6.5 cm.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source

Where Citrine is found (11)

Bolivia

Brazil

Mexico

Namibia

South Africa

Spain

United States

Identity

Variety of
Quartz
Also called
Bohemian topaz; citron; kundalini quartz; lemon quartz
Strunz
4.DA · 4 Oxides and hydroxides
IMA status
Variety
Name origin
From 'citrina', for a colour as yellow as a citron (lemon).
Elements
Si, O

Physical properties

Color
Pale yellow to brownish orange; finest gem colour is saturated yellow to reddish orange; sometimes yellow-green
Streak
White
Luster
Vitreous luster
Transparency
Transparent
Mohs hardness
7
Density
2.65–2.66 g/cm³
Cleavage / fracture
Cleavage rarely observable and poor; fracture conchoidal; brittle

Crystallography

Crystal system
Trigonal
Space group
P3121 or P3221 (enantiomorphic pair)
Structure
Framework of corner-sharing SiO4 tetrahedra (tectosilicate); cell a = 4.9135 Å, c = 5.4050 Å, Z = 3.
Typical habit
As quartz: prismatic crystals with rhombohedral terminations, striated parallel to the c-axis; also drusy aggregates
Twinning
Very common in quartz: Dauphiné law (penetration), Brazil law (penetration) and Japan law (contact)
Optical data
Uniaxial (+); omega = 1.544, epsilon = 1.553; birefringence about 0.009

Formation and use

Formation
Natural citrine forms where aluminium-rich quartz growth zones are irradiated; it occurs in the same settings as other quartz. Natural amethyst-citrine bicoloured crystals occur in the Anahi mine in Bolivia, and field and experimental work show this combination is natural and not a laboratory product.
Uses
Faceted gemstone; sizes up to about 20 carats are readily available in jewellery. Also collected as crystal specimens.
Stability and care
Heating pales natural citrine above roughly 200-500 C and irradiation can restore the colour. Heat-treated amethyst colours are stable under normal storage and wear. Most commercial citrine is heat-treated amethyst; such treatment is not always disclosed. Avoid dry grinding, which produces hazardous quartz dust.

Related minerals

Related minerals
Quartzamethystsmoky quartzametrine
Polymorphs
Cristobalitetridymitecoesitestishovite
Can be confused with
Topaz (harder, Mohs 8historically confused with citrine)heat-treated amethystheat-treated smoky quartziron-oxide-stained quartz

Sources

  1. SRC-084 · Book
    Handbook of Mineralogy - QuartzAnthony, J.W.; Bideaux, R.A.; Bladh, K.W.; Nichols, M.C. · 2001 · Mineralogical Society of America / Mineral Data Publishing
  2. SRC-085 · Database
    Quartz (Mindat.org mineral page)Mindat.org / Hudson Institute of Mineralogy
  3. SRC-100 · Database
    Citrine: Mineral information, data and localitiesMindat.org
  4. SRC-101 · Website
    Citrine DescriptionGemological Institute of America (GIA)
  5. SRC-113 · Website
    Rio Grande citrineSkyjems (seller)
  6. SRC-117 · Article
    Amethyst-citrine (ametrine) from the Anahi mine, BoliviaVasconcelos, L.; et al. (as given in the URL; not verified) · 1994 · Gems & Gemology (Spring 1994)

Draft data from the Provenite workbook. Check entries against the cited sources before relying on them. Photos are open-licence images from Wikimedia Commons; the author and licence are given with each photo.