Pargasite Value, Price, and Jewelry Information

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

Pargasite

The amphibole group is very large and extremely complex and contains numerous distinct species that vary subtly in chemistry and physical properties. Pargasite and ferropargasite are calcic amphiboles that generally are lumped together as hornblende,even though up to 16 distinct minerals belong to this group, including actinolite. The identity of a specific amphibole is determined (ideally) by a chemical analysis or by detailed measurements of density, color, and optical data. There are undoubtedly a great many localities that could potentially yield cuttable crystals.

Pargasite Information

Data Value
Name Pargasite
Colors Light brown to brown, grayish black, bluish green, dark green.
Crystallography Monoclinic; crystals prismatic, also massive, compact or granular.
Refractive Index 1.613-1.635
Luster Vitreous.
Hardness 5-6
Fracture Uneven, parting 2 directions
Specific Gravity 3.069-3.181
Birefringence 0.022
Cleavage Perfect 1 direction
Stone Sizes Pargasite from Nova Scotia has yielded faceted gems in the 2-3 carat range. The mineral, though abundant and widespread, seldom occurs in crystals transparent enough for cutting stones over ½ carat.
Luminescence None.
Luminescence Present No
Transparency Transparent to translucent.
Absorption Spectrum Not diagnostic.
Formula

NaCa2(Mg,Fe)4Al(5i6Al2)O22(OH)2

Pleochroism

Colorless/very light brown/light brown; colorless/bluish green/bluish green; greenish yellow/green/bluish green.

Optics

a = 1.613; β = 1.618; γ = 1.635. Biaxial (+), 2V = 120°.

Optic Sign Biaxial +

See also: Actinolite; Hornblende; Amphibole; Series to Ferropargasite if Fe exceeds Mg.

Amphibole Group; closely related to Hornblende.

Optics: a=1.613; β= 1.618; γ=1.635.

Biaxial (+), 2V: 120°.

Occurrence: A widespread component of igneous and metamorphic rocks.

Pargas, Finland.

Fresno, California; Burlington, Pennsylvania.

Scotland; Sweden; USSR; Austria; Venezuela.

Baffin Island, Nova Scotia, Canada.

Comments: The amphibole group is very large and extremely complex and contains numerous distinct species that vary subtly in chemistry and physical properties. Pargasite and ferropargasite are calcic amphiboles that generally are lumped together as hornblende, even though up to 16 distinct minerals belong to this group, including actinolite. The identity of a specific amphibole is determined (ideally) by a chemical analysis or by detailed measurements of density, color, and optical data. There are undoubtedly a great many localities that could potentially yield cuttable crystals.

Name: After the locality, Pargas, Finland.

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