Brookite Value, Price, and Jewelry Information


Brookite
Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons

Brookite is a very dark-colored mineral, transparent only in small fragments. Cuttable crystals are exceedingly rare, and attractive-looking cut stones are among the rarest of all gems. Most stones are in private collections.

Brookite Value

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Brookite Information

DataValue
NameBrookite
Crystallography Orthorhombic. Occurs only in crystals; tabular, prismatic, pyramidal; often striated.
Colors Brown, yellow brown, reddish brown, dark brown to black; rarely blue.
Luster Adamantine to submetallic.
Hardness 5.5 - 6
Specific Gravity 4.14 normal; 3.87 – 4.14.
Birefringence 0.122 – 0.157
Cleavage Indistinct
Dispersion Strong, ~ 0.131
Stone SizesAlways less than 1-2 carats; larger stones are opaque.
Luminescence None.
FormulaTiO2
Pleochroism Strong: yellow-brown/ reddish-brown/ orange to golden brown. An hourglass-shaped zonal coloration is sometimes seen in bluish crystals.

OPTICS: a = 2.583; β = 2.584; γ = 2.700 – 2.740

Biaxial (+) 

OCCURRENCE: In gneisses, schists and sometimes in igneous rocks; contact deposits.

North Carolina; Somerville, Massachusetts; Maine; California.

Magnet Cove, Arkansas: contact metamorphic rocks.

Ellenville, New York: hydrothermal deposits.

Tirol, Switzerland: typical Alpine deposits

Minas Gerais, Brazil: Dartmoor, England; France; USSR.

COMMENTS: Brookite is a very dark-colored mineral, transparent only in small fragments. Cuttable crystals are exceedingly rare, and attractive-looking cut stones are among the rarest of all gems. Most stones are in private collections.

NAME:  After the English mineralogists and crystallographer J.H. Brooke.