Sedimentary
Jasper (specifically Fancy or Polychrome Jasper)
Silicon Dioxide (SiO2) - Chalcedony
Hardness: 6.5-7 (Mohs scale); Color: Variegated red, tan, sage green, and blue-grey; Luster: Dull to waxy; Texture: Fine-grained, microcrystalline quartz; Fracture: Conchoidal.
- Hardness
- 6
- Color
- Variegated red, tan, sage green, and blue-grey
- Luster
- Dull to waxy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Variegated red, tan, sage green, and blue-grey; Luster: Dull to waxy; Texture: Fine-grained, microcrystalline quartz; Fracture: Conchoidal.
Formation & geological history
Formed from silica-rich groundwater that permeates through volcanic ash or sedimentary beds. The vibrant bandings and swirls are created by iron oxides and other mineral impurities during the lithification process over millions of years.
Uses & applications
Predominantly used as a semi-precious gemstone for cabochons, beads, and carved decorative objects. Also used in lapidary arts for tumbling or as a 'landscape stone' in high-end masonry.
Geological facts
Jasper is incredibly opaque compared to other forms of chalcedony like agate. The specific 'Polychrome' or 'Fancy' variety seen here is often associated with the desert regions of Madagascar or the Southwestern US.
Field identification & locations
Identify by its 'swirly' or banded opaque colors and its ability to scratch glass but not be scratched by a steel knife. It is commonly found in desert environments or eroded riverbeds.
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