Brucite is extremely difficult to cut, and only a few faceted stones in the ½-1 carat size range are known.
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
|Crystallography||Hexagonal; tabular crystals, platy aggregates. Manganoan variety sometimes acicular. Also foliated, massive, fibrous, scaly.|
|Colors||White, pale green, gray, bluish. Manganoan variety yellow to brownish-red, brown|
|Luster||Waxy to vitreous; pearly on cleavages.|
|Fracture||Sectile, plates flexible.|
|Cleavage||Perfect basal cleavage.|
|Stone Sizes||Brucite is very rarely facetable. The major source for cuttable material is Asbestos, Quebec, which has yielded pale blue gems up to 1+ carats.|
|Pleochroism||None; colorless in transmitted light.|
OPTICS: o= 1.559-1.590; e= 1.580-1.600
Uniaxial (+); sometimes biaxial with small 2V.
OCCURRENCE: In low temperature hydrothermal veins in serpentine, chloritic and dolomite schists, and metamorphic limestones.
Asbestos, Quebec, Canada: Fibrous masses up to several feet in length; also cuttable pale blue masses.
Hoboken, New Jersey: Fibrous aggregates.
Lancaster County, Pennsylvania: Plates nearly 20 cm across.
Brewster, New York: Small crystals.
California; Italy; Scotland; Sweden (Manganoan var.),
COMMENTS: Brucite is extremely difficult to cut, and only a few faceted stones in the ½-1 carat size range are known.
NAME: After Archibald Bruce, an early American mineralogist who first described the species.