SERPENTINE: Williamsite, Maryland (2.3). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Serpentine
Bowenite is usually blue-green, yellow-green, or dark green and translucent; it is used for carving, knife handles, and so forth, and in jewelry. Williamsite contains dark octahedral crystals of chromite, and patches of white brucite (magnesium hydroxide).Ricolite is a banded serpentine from Rico, New Mexico. Satelile is a serpentine pseudomorph after asbestiform tremolite from Maryland and California, grayish to greenish blue. Pseudophite or styrian jade is from Austria and is an aluminous serpentine, with hardness 2.5, refractive index 1.57, and density 2.69. Chrysotile, in fibrous form, is best known as asbestos and is widely used in industry for its physical properties.
A group of minerals.
Serpentine is a group of four species with the same composition but different properties: anitgorite, chrysotile and lizardite. All may form rocks that are cut and polished.
Occurrence: Serpentine forms due to the alteration of basic and ultra basic rocks. ln some instances it may be mistaken for nephrite jade.
SERPENTINE: Pakistan (~ 4 inches long). Photo © Joel E. Arem, PhD, FGA. Used with permission.
Bowenite (a translucent green or blue-green variety of antigorite).
New Zealand: dark bluish green, S.G. 2.67.
Delaware River, Pennsylvania: dark green.
Smithfield, Rhode Island: dark green.
China: light yellowish green.
Afghanistan: green.
Transvaal, South Africa: banded in green shades.
Williamsite (a very translucent variety of antigorite): apple green color.
Rock Springs, Maryland: best-known locality; may contain Cr and be deep green in color; R.l. (mean) 1.56, S.G. 2.6-2.62, hardness 4.5.
Lizardite
Kashmir, India; Scotland: gray, green. S.G. 2.51.
Lizard Peninsula, Cornwall, England: veined various colors; S.G. 2.45.
South Africa; Austria; Anglesey; Wales.
Ireland: mixture of serpentine and carbonates. Locally known as Connemara marble: mean R.I. 1.56, S.G. 2.48-2.77; absorption line at 4650.
Antigarite: Faceted gem found in material from Pakistan, yellowish-green, nearly transparent; indices 1.559—1.561, birefringence 0.001-0.002.
Verd Antique: a green serpentine veined with calcite and other minerals. Found in Greece; Italy; Egypt; Vermont.
Comments: Bowenite is usually blue-green, yellow-green, or dark green and translucent; it is used for carving, knife handles, and so forth, and in jewelry. Williamsite contains dark octahedral crystals of chromite, and patches of white brucite (magnesium hydroxide). Ricolite is a banded serpentine from Rico, New Mexico. Satelile is a serpentine pseudomorph after asbestiform tremolite from Maryland and California, grayish to greenish blue. Pseudophite or styrian jade is from Austria and is an aluminous serpentine, with hardness 2.5, refractive index 1.57, and density 2.69. Chrysotile, in fibrous form, is best known as asbestos and is widely used in industry for its physical properties.
Names: Serpentine from the serpent-like markings seen in a serpentine marble; chrysotile is from the Greek chrysos (golden) and tilos (fibrous), aptly describing the properties of this mineral. Antigorite and lizardite are named after the type localities, Antigorio Valley, Piedmont. Italy, and Lizard, Cornwall, England. Bowenite is after G. T Bowen, who studied material from Rhode Island (though he misidentified the material as nephrite). Williamsite is named after L. W. Williams, who first found it.
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