mineral
Chalcedony Pebble (Carnelian / Quartz Pebble)
Silicon Dioxide (SiO2)
Hardness: 6.5-7 on Mohs scale; Color: yellowish-orange to light brownish-tan; Luster: waxy to greasy; Crystal Structure: Trigonal (microcrystalline); Cleavage: none (conchoidal fracture); Specific Gravity: ~2.6
- Hardness
- 6
- Color
- yellowish-orange to light brownish-tan
- Luster
- waxy to greasy
Identified More mineral →
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Physical properties
Hardness: 6.5-7 on Mohs scale; Color: yellowish-orange to light brownish-tan; Luster: waxy to greasy; Crystal Structure: Trigonal (microcrystalline); Cleavage: none (conchoidal fracture); Specific Gravity: ~2.6
Formation & geological history
Formed through the deposition of silica-rich fluids in cavities of volcanic or sedimentary rocks. Over time, weathering and water erosion smooth the specimen into a stream or beach pebble.
Uses & applications
Used in lapidary arts, jewelry (cabochons, beads), decorative landscaping, and gem/rock collecting.
Geological facts
Microcrystalline quartz variants like chalcedony and agate have been used since prehistoric times to make tools, seals, and ornamental objects due to their toughness and lack of cleavage.
Field identification & locations
Identified in the field by its waxy luster, hardness (scratches glass), smooth water-worn surface, and translucency when held against a light source. Found in riverbeds, gravel pits, and coastal areas worldwide.
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Mineral