Chalcedony
What is Chalcedony?
Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. These are both silica minerals, but they differ in their crystal structure. Chalcedony has a waxy luster and can be translucent or semi-transparent. It occurs in a wide range of colors, often banded or patterned.
Optical Properties
- Refractive Index
- 1.530-1.540
- Birefringence
- 0.004
- Pleochroism
- Weak to absent
- Optical Character
- uniaxial (+)
- Dispersion
- 0.013
Chalcedony Market Value Calculator
Estimate the market value of Chalcedony using size, quality, and finish. This preview calculator is for quick context and is not a formal appraisal.
Chalcedony Localities Map
See where Chalcedony is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Map preview
North ZoneCentral RidgeSouth Basin
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© Robert M. Lavinsky
© Robert M. Lavinsky
Quick Facts
Physical Properties
- Color
- White, gray, blue, brown, yellow, pink, red, and green
- Hardness (Mohs)
- 6.5 to 7
- Density
- 2.58 to 2.64 g/cm³
- Streak
- White
Chemical Properties
- Chemical Formula
- SiO2
- Elements
- Silicon, Oxygen
Also Known As
ChalcedonAgateOnyxJasper
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