mineraloid
Pearl
Calcium carbonate (CaCO3) - mainly Aragonite with Conchiolin
Hardness: 2.5-4.5 (Mohs scale); Color: White, cream, silver, pink, black; Luster: Pearly (iridescent); Structure: Amorphous (microcrystalline aragonite); Specific gravity: 2.60-2.85
- Hardness
- 2
- Color
- White, cream, silver, pink, black
- Luster
- Pearly (iridescent)
Identified More mineraloid →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 2.5-4.5 (Mohs scale); Color: White, cream, silver, pink, black; Luster: Pearly (iridescent); Structure: Amorphous (microcrystalline aragonite); Specific gravity: 2.60-2.85
Formation & geological history
Biogenic formation within the soft tissue (mantle) of a living shelled mollusk. It is formed by the secretion of nacre around an irritant.
Uses & applications
Primarily used in jewelry (necklaces, earrings, rings) and as a traditional gemstone in various cultures.
Geological facts
Pearls are the only gemstones made by living creatures. The most famous pearl is 'La Peregrina,' which was owned by kings of Spain and later Elizabeth Taylor.
Field identification & locations
Identify by the 'tooth test' (feels gritty against teeth) or by checking for concentric growth layers under magnification. Found in marine and freshwater environments worldwide.
More like this
Other mineraloid specimens
Amber
Succinite (Organic Mineraloid)
mineral
Mahogany Obsidian
Volcanic glass (high silica) with inclusions of Magnetite or Hematite
igneous
Obsidian
Volcanic glass (SiO2 + impurities)
igneous
Black Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Fulgurite
Fulgurite (Lechatelierite)
metamorphic
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Igneous