Provenite

About Emerald

Be3Al2Si6O18

Emerald is the green to bluish-green variety of beryl. Its colour comes from trace chromium and/or vanadium, with iron influencing the exact shade; paler material is sold as green beryl, and the boundary is set by comparison stones in gem laboratories. Eye-visible inclusions (the garden-like 'jardin') are typical, and Colombian stones often contain three-phase inclusions of a salt crystal, liquid and a gas bubble. Lab-grown emerald has essentially the same chemical, physical and optical properties as natural emerald.

Show 12 localities on the map

Photos of Emerald

Light green, partly gemmy emerald crystal of about 1.7 cm from the Coscuez Mine.
Emerald · Coscuez Mine
Light green, partly gemmy emerald crystal of about 1.7 cm from the Coscuez Mine.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Bright green emerald crystal of 4.3 cm in schist matrix from the Panjshir Valley.
Emerald · Panjshir Valley emerald deposits
Bright green emerald crystal of 4.3 cm in schist matrix from the Panjshir Valley.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Light green emerald crystal of 1.5 cm on mica schist, an old specimen from the Habach valley.
Emerald · Habach valley (Habachtal), Hohe Tauern
Light green emerald crystal of 1.5 cm on mica schist, an old specimen from the Habach valley.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Cluster of about two dozen bright green emerald crystals up to 1.2 cm from Serra das Eguas, Brumado.
Emerald · Serra das Eguas (Brumado)
Cluster of about two dozen bright green emerald crystals up to 1.2 cm from Serra das Eguas, Brumado.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
A 6 cm emerald crystal set in calcite and shale matrix from the Muzo Mine.
Emerald · Muzo Mine
A 6 cm emerald crystal set in calcite and shale matrix from the Muzo Mine.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Light green emerald crystal of 2.7 cm with a modified pinacoid termination from Jos, Nigeria.
Emerald · Jos Plateau
Light green emerald crystal of 2.7 cm with a modified pinacoid termination from Jos, Nigeria.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Large doubly terminated emerald crystal with embedded mica from Malyshevo, Urals.
Emerald · Malyshevo emerald mines (Malyshevskoe deposit, Mariinsky mine)
Large doubly terminated emerald crystal with embedded mica from Malyshevo, Urals.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Light green prismatic emerald crystals up to 11 mm on matrix from Pizzo Marcio, Vigezzo valley.
Emerald · Pizzo Marcio emerald pegmatites (Trontano)
Light green prismatic emerald crystals up to 11 mm on matrix from Pizzo Marcio, Vigezzo valley.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source

Where Emerald is found (12)

Afghanistan

Australia

Austria

Brazil

Colombia

Italy

Nigeria

Russia

Identity

Variety of
Beryl
Strunz
9 Silicates
IMA status
Variety
Elements
Be, Al, Si, O

Physical properties

Color
Green to bluish green; material too light in tone is called green beryl rather than emerald
Streak
White
Luster
Vitreous luster
Transparency
Variable
Mohs hardness
7.5–8
Density
2.63–2.97 g/cm³
Cleavage / fracture
Imperfect cleavage on {0001}; conchoidal to uneven fracture; brittle

Crystallography

Crystal system
Hexagonal
Space group
P6/mcc
Typical habit
Hexagonal prisms, commonly with a flat pinacoid termination; also columnar or granular masses (beryl habits)
Twinning
Rare
Optical data
Uniaxial (-); nω = 1.567-1.610, nε = 1.565-1.599 for beryl, rising with alkali content; pleochroism weak to distinct

Formation and use

Formation
Beryl forms in granites and granite pegmatites, in mafic metamorphic rocks and in low- to high-temperature hydrothermal veins; emerald forms where chromium and/or vanadium are available to the growing beryl. Colombian deposits (Muzo, Chivor) are classic sources of exceptional green crystals.
Uses
Gemstone; mineral specimens
Stability and care
More brittle than corundum, and nearly all emeralds contain fractures, so stones can be damaged in cutting, setting and wear. An estimated 99% of cut emeralds are clarity-enhanced by filling surface-reaching fissures with oil (traditionally cedarwood oil) or resins; these fillers can leak or dry out, so avoid ultrasonic cleaners, hot or soapy water and solvents such as acetone or alcohol.

Related minerals

Related minerals
Beryl

Sources

  1. SRC-266 · Book
    Handbook of Mineralogy - BerylAnthony, J.W.; Bideaux, R.A.; Bladh, K.W.; Nichols, M.C. · 2001 · Mineralogical Society of America / Mineral Data Publishing
  2. SRC-813 · Website
    Emerald Gemstone | Emerald Stone - GIAGemological Institute of America · GIA Gem Encyclopedia
  3. SRC-814 · Website
    Emerald Quality FactorsGemological Institute of America · GIA Gem Encyclopedia
  4. SRC-815 · Website
    A Guide to Emerald EnhancementsBergman, J. · 2021 · International Gem Society

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.