Simpsonite Value, Price, and Jewelry Information

SIMPSONITE: Brazil (0.27). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Simpsonite

Simpsonite is an extremely rare gemstone. The material from Western Australia is bright yellow-orange and very beautiful. The mineral is hard and durable, with no cleavage, and could easily become a popular gemstone if it were more abundant. Gems over 1 carat should be considered extremely rare because clean material is a very small percentage of the limited supply of simpsonite that has been found.

Simpsonite Information

Data Value
Name Simpsonite
Colors Colorless, pale yellow, cream white, light brown, orange.
Crystallography Hexagonal. Crystals tabular, prismatic; also in crystalline masses.
Refractive Index 1.976-2.034
Luster Vitreous, adamantine.
Hardness 7-7.5
Fracture Conchoidal
Specific Gravity 5.92-6.84
Birefringence 0.058
Cleavage None
Stone Sizes Crystals have been found up to 5 cm but only tiny stones have been cut from available rough. Ln general, stones are only seen from Brazil and Australia. A typical size is 0.5-1 carat.
Luminescence In SW, bright blue-white (Western Australia), bright pale yellow (Bikita, Zimbabwe), medium pale yellow (Ecuador) or light blue (Paraiba, Brazil).
Luminescence Present Yes
Luminescence Type Fluorescent, UV-Short
Transparency Transparen to translucent.
Absorption Spectrum Not diagnostic.
Formula

Al4Ta3O13(OH).

Pleochroism

None.

Optics

= 2.034; e = 1.976. Uniaxial (-).

Optic Sign Uniaxial -

Optics: o= 2.034; e=1.976.

Uniaxial (-).

Occurrence: In granite pegmatites, usually with biotite.

Bikita, Zimbabwe; Alto do Giz, Ecuador; Kola Peninsula, USSR.

Onca and Paraiba, Brazil: facetable material.

Tabba Tabba. Western Australia: facetable yellowish crystals.

Comments: Simpsonite is an extremely rare gemstone. The material from Western Australia is bright yellow-orange and very beautiful. The mineral is hard and durable, with no cleavage, and could easily become a popular gemstone if it were more abundant. Gems over 1 carat should be considered extremely rare because clean material is a very small percentage of the limited supply of simpsonite that has been found.

Name: After Dr. E. S. Simpson, former government mineralogist of Western Australia.