Agate
What is Agate?
Agate is a cryptocrystalline form of silica, essentially chalcedony exhibiting a fine grain and vibrant color variations. Agates are primarily formed within volcanic and metamorphic rocks. The unique banding and patterns are a result of the gradual deposition of silica-rich fluids within cavities. These cavities can be of various shapes and sizes, leading to the diverse appearances of agate. The different colors and patterns are due to the presence of various impurities.
Optical Properties
- Refractive Index
- 1.530-1.540
- Pleochroism
- None
- Optical Character
- Uniaxial positive
- Dispersion
- 0.013
Discover Values
Agate Market Value Calculator
Estimate the market value of Agate using size, quality, and finish. This preview calculator is for quick context and is not a formal appraisal.
Agate Localities Map
See where Agate is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
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Quick Facts
Physical Properties
- Color
- White, gray, blue, red, orange, yellow, green, brown, black, pink, purple
- Hardness (Mohs)
- 6.5-7
- Density
- 2.58-2.64 g/cm³
- Streak
- White
- Luster
- Vitreous
- Crystal System
- Hexagonal
Chemical Properties
- Chemical Formula
- SiO2
- Elements
- Si, O
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