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demantoid
thumb|Garnet demantoid - Antetezambato, Ambanja District, Diana (Northern) Region, Antsiranana Province, Madagaskar. Demantoid is the green gemstone variety of the mineral andradite, a member of the garnet group of minerals. Andradite is a calcium- and iron-rich garnet. The chemical formula is Ca3Fe2(SiO4)3 with chromium substitution as the cause of the demantoid green color. Ferric iron is the cause of the yellow in the stone.
Key facts
- Mineral.name
- Demantoid
- Mineral.boxbgcolor
- 366c25
- Mineral.boxtextcolor
- FFFFFF
- Mineral.image
- Andradite-Stilbite-Ca-dem05a.jpg
- Mineral.imagesize
- 260px
- Mineral.caption
- Demantoid with stilbite
- Mineral.formula
- Ca3Fe2Si3O12
- Mineral.color
- light to deep green
- Mineral.system
- cubic
- Mineral.mohs
- 6.5–7.0
- Mineral.luster
- adamantine
- Mineral.refractive
- 1.880–1.889
- Mineral.opticalprop
~6 min read
Article
5 sectionsContents
- History
- Appearance
- Horsetails
- References
- External links
thumb|Garnet demantoid - Antetezambato, Ambanja District, Diana (Northern) Region, Antsiranana Province, Madagaskar. Demantoid is the green gemstone variety of the mineral andradite, a member of the garnet group of minerals. Andradite is a calcium- and iron-rich garnet. The chemical formula is Ca3Fe2(SiO4)3 with chromium substitution as the cause of the demantoid green color. Ferric iron is the cause of the yellow in the stone.
It has the misnomers olivine and Uralian emerald.