sedimentary
Banded Agate (Onyx type)
Silicon Dioxide (SiO2)
Hardness: 6.5-7 Mohs; Color: Alternating bands of white, tan, and grey; Luster: Vitreous/Waxy; Crystal Structure: Microcrystalline; Cleavage: None
- Hardness
- 6
- Color
- Alternating bands of white, tan, and grey
- Luster
- Vitreous/Waxy
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Physical properties
Hardness: 6.5-7 Mohs; Color: Alternating bands of white, tan, and grey; Luster: Vitreous/Waxy; Crystal Structure: Microcrystalline; Cleavage: None
Formation & geological history
Formed in cavities within volcanic or sedimentary rocks through the deposition of silica from groundwater. The bands represent different pulses of mineral-rich fluids over geological time.
Uses & applications
Predominantly used for ornamental purposes, cabochons for jewelry (as seen here in the pendant), and lapidary carvings.
Geological facts
Banded agate has been used in jewelry since Neolithic times; it was highly prized in Ancient Egypt and Greece for protective amulets and signet rings.
Field identification & locations
Identify by its distinct parallel or concentric banding and translucent properties when held to light. Modern sources include Brazil, Uruguay, and India.
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