Opal and Siderite Optical Properties

Opal

Siderite

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1 Optical Properties

1.1 Luster

Vitreous, Pearly

Pearly

1.2 Pleochroism

None

Not Available

1.3 Dispersion

NoneNA

0.007 1

1.4 Transparency

Transparent, Translucent, Transparent to translucent

Transparent, Translucent

1.5 Refractive Index

1.37-1.521.633-1.875

1 3.25

1.6 Optic Character

Not Available

1.7 Crystal System

Trigonal

1.8 Birefringence

Not Available0.242

0 0.296

1.9 Clarity

Transparent

Opal and Siderite Optic Character

Opal and Siderite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Opal and Siderite 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 Opal and Siderite 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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Opal and Siderite Transparency

Similar to their colors, Opal and Siderite 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, Opal is Translucent, Transparent and Transparent to translucent while Opal is Translucent, Transparent and Transparent to translucent in appearance.