Proustite and Allanite Optical Properties

Proustite

Allanite

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1 Optical Properties

1.1 Luster

Adamantine

Not Available

1.2 Pleochroism

Moderate; cochineal-red to blood-red

Not Available

1.3 Dispersion

NANA

0.007 1

1.4 Transparency

OpaqueUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) Rarely transparentMore from other references

Not Available

1.5 Refractive Index

2.792-3.0871

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

Not Available

1.8 Birefringence

0.295-0.2960.013-0.036

0 0.296

1.9 Clarity

OpaqueUlrich Henn and Claudio C. Milisenda

Not Available

Proustite and Allanite Optic Character

Proustite and Allanite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Proustite and Allanite Physical Properties like crystallographic symmetry, pleochroism,etc. in the crystal. Some of the optical properties are refractive index, luster, optic character, pleochroism etc. Prominent among these is Proustite and Allanite optic character. You might have noticed your gemologist rotating the gemstone while testing it. Rotating a gemstone along its optic axis helps in determining its optic character.

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Proustite and Allanite Transparency

Similar to their colors, Proustite and Allanite transparency can also be used as criteria for their primary identification. Although transparency cannot be the only criteria for gemstone identification, it can efficiently used in gemstone grading. Talking about their transparency, Proustite is Gemmological Tables (2004) Rarely transparentMore from other references and OpaqueUlrich Henn and Claudio C. Milisenda while Proustite is Gemmological Tables (2004) Rarely transparentMore from other references and OpaqueUlrich Henn and Claudio C. Milisenda in appearance.