mineral
Natural Gemstone Cabochons (Ruby, Moonstone, Emerald, Citrine)
Ruby (Al2O3:Cr), Moonstone (KAlSi3O8), Emerald (Be3Al2(SiO3)6:Cr), Citrine (SiO2)
AI-generated identification · may be incorrectVarying hardness (7.5-9 on Mohs), Vitreous luster, high saturation colors, trigonal to orthorhombic crystal systems, density ranging from 2.6 to 4.0 g/cm3.
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Physical properties
Varying hardness (7.5-9 on Mohs), Vitreous luster, high saturation colors, trigonal to orthorhombic crystal systems, density ranging from 2.6 to 4.0 g/cm3.
Formation & geological history
Formed in metamorphic (Ruby/Emerald), igneous (Citrine), and pegmatitic (Moonstone) environments over millions of years.
Uses & applications
Primarily used in high-end jewelry, decorative arts, and as investment-grade specimens for collectors.
Geological facts
Rubies are actually red sapphires; both are the mineral corundum. Emeralds are the rarest of the four shown here, often containing distinct 'jardin' inclusions.
Field identification & locations
Identify by specific gravity, refractive index, and inclusion patterns. Common locations include Brazil, Myanmar, Sri Lanka, and Madagascar.
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Other mineral specimens
Gneiss or Schist
Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Tumbled granite
Granite, a coarse-grained felsic intrusive igneous rock
igneous
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Granite
Granite (Phaneritic intrusive igneous rock)
igneous