Demantoid
A variety of Andradite
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About Demantoid
Formula:
Ca3Fe3+2(SiO4)3
Name:
Named by Nils Gustaf Nordenskiøld from the archaic German word "Demant" which means "diamond" in allusion to its very high brilliance resembling that of diamond.
A variety of Andradite
A green variety of andradite.
Originally described from Telyanskaya River, Kamennaya Telyana, Nizhnii-Tagil (Mednorudyanskoye) Cu Deposit, Nizhnii Tagil, Sverdlovskaya Oblast', Urals Region, Russia (https://www.mindat.org/loc-2803.html).
"Horsetail" inclusions are usually empty tubular hollows (sometimes filled with serpentine).
Visit gemdat.org for gemological information about Demantoid.
A green variety of andradite.
Originally described from Telyanskaya River, Kamennaya Telyana, Nizhnii-Tagil (Mednorudyanskoye) Cu Deposit, Nizhnii Tagil, Sverdlovskaya Oblast', Urals Region, Russia (https://www.mindat.org/loc-2803.html).
"Horsetail" inclusions are usually empty tubular hollows (sometimes filled with serpentine).
Visit gemdat.org for gemological information about Demantoid.Unique Identifiers
Mindat ID:
1258 (as Demantoid)
223 (as Andradite)
223 (as Andradite)
Long-form identifier:
mindat:1:1:1258:0 (as Demantoid)
mindat:1:1:223:5 (as Andradite)
mindat:1:1:223:5 (as Andradite)
GUID
(UUID V4):
(UUID V4):
22eb6b56-c719-43b7-b8c4-39abdc7e380a (as Demantoid)
c21d3fbc-f620-4327-a4da-8e733204786d (as Andradite)
c21d3fbc-f620-4327-a4da-8e733204786d (as Andradite)
Pronunciation of Demantoid
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Debbie Woolf | United Kingdom |
Chemistry of Demantoid
Mindat Formula:
Ca3Fe3+2(SiO4)3
Elements listed:
Chemical Analysis
Oxide wt%:
| 1 | 2 | |
|---|---|---|
| SiO2 | 36.7 % | 35.6 % |
| TiO2 | 0.71 % | 0 % |
| Al2O3 | 7.84 % | 2.78 % |
| Cr2O3 | 1.18 % | % |
| FeO | 15.83 % | 1.4 % |
| MnO | 0.15 % | 0.15 % |
| MgO | 0.29 % | 0 % |
| CaO | 33.91 % | 31.99 % |
| Fe2O3 | % | 24.75 % |
| H2O | % | 0.01 % |
| Total: | 96.61 % | 96.68 % |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Belqeys Mountain, Takab County, West Azerbaijan Province, Iran | EMPA analysis of green "demantoid" from Baba Nazar, Iran | |
| 2 | Tubussis Farm 22, Dâures Constituency, Erongo Region, Namibia | EMPA analysis of a zoned crystal with an andradite core and grossular rim. This analysis is from the garnet core. The analysis was performed using a Cameca SX100 electron microprobe at the Research School of Earth Sciences (RSES), the Australian National University (ANU) with operating conditions of 15 kV acceleration voltage, and 20 nA beam current focused to 1 mm. Natural and synthetic minerals were used as standards. Fe valence states is calculted. |
Crystallography of Demantoid
Morphology:
spherical aggregates
Other Language Names for Demantoid
Simplified Chinese:翠榴石
Common Associates
Associated Minerals Based on Photo Data:
| 67 photos of Demantoid associated with Amphibole Supergroup | AB2C5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 |
| 59 photos of Demantoid associated with Quartz | SiO2 |
| 37 photos of Demantoid associated with Asbestos | |
| 21 photos of Demantoid associated with Chrysotile | Mg3(Si2O5)(OH)4 |
| 14 photos of Demantoid associated with Serpentine Subgroup | D3[Si2O5](OH)4 |
| 11 photos of Demantoid associated with Serpentinite | |
| 11 photos of Demantoid associated with Diopside | CaMgSi2O6 |
| 10 photos of Demantoid associated with Calcite | CaCO3 |
| 8 photos of Demantoid associated with Muscovite | KAl2(AlSi3O10)(OH)2 |
| 8 photos of Demantoid associated with Andradite | Ca3Fe3+2(SiO4)3 |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Demantoid
mindat.org URL:
https://www.mindat.org/min-1258.html
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Demantoid
Reference List:
Localities for Demantoid
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Afghanistan | |
| Rob Lavinsky specimen | |
| Andrew Debnam collection | |
Argentina | |
| Dr. Jorge Dascal and Gunnar Färber ... |
Asia | |
| Grant (2001) | |
Canada | |
| Amabili et al. (2009) |
| www.alpinegems.net | |
China | |
| Yanling Tang (2005) |
DR Congo | |
| Gübelin et al. (1976) | |
France | |
| Demargne M. (2014) |
Germany | |
| F. Müller: "Bayerns steinreiche Ecke" et al. (Hof) |
| F. Müller: "Bayerns steinreiche Ecke" et al. (Hof) |
| Weiß (1990) |
Iran | |
| Gems and Gemology +1 other reference |
| Vachik Hairapetian collection +2 other references |
Italy | |
| De Michele (1972) |
| Brugnatelli (1903) +5 other references | |
| Grill (1922) +4 other references | |
| Del Caldo et al. (1973) +1 other reference |
| Castello (1978) +1 other reference | |
| Matteo Chinellato collection | |
| C.M. Gramaccioli (1975) | |
| Domenico Preite Collection & Photo +1 other reference |
| Gramaccioli (1962) | |
| De Michele (1974) |
| Tabacchi (1972) |
| Gramaccioli (1962) +2 other references | |
| Bedognè et al. (1993) | |
| Giovanni Scapin specimen +1 other reference | |
| Gramaccioli (1975) |
| Bonifazi (2020) |
| Sammartino F. | |
Japan | |
| Specimens on sale at TIMA show |
Madagascar | |
| 90 +4 other references |
Mexico | |
| GIA 2019 |
| www.mindat.org (n.d.) |
| Mineralogical Record Special Issue III +1 other reference | |
Namibia | |
| von Bezing (2007) |
| Bezing et al. (2007) | |
| Rob Lavinsky +3 other references | |
| Locker (2011) | |
| Manfred Lehrl (pers. comm. to U. Kolitsch, 2011) | |
| Bezing et al. (2007) | |
| Scovil (1998) |
| von Bezing (2007) |
| von Bezing (2007) | |
Pakistan | |
| Jose Zendrera Collection |
| Adamo (2015) |
| Zhang et al. (2024) | |
Russia | |
| Grant (2001) +1 other reference |
| Kissin AY et al. (2021) | |
| www.pegmatite.ru (2009) +1 other reference |
| [World of Stones 95:5-6 |
| Mason (1976) |
| Handbook of Mineralogy. +1 other reference | |
| |
| Sehrig (2008) +1 other reference |
Slovakia | |
| Duda |
| Štubňa et al. (2019) | |
Spain | |
| |
| Madon et al. (1991) +1 other reference |
Sri Lanka | |
| Ceylon Aluvial Mine (Book, Co. 2002) |
Switzerland | |
| Romani (2000) +1 other reference |
| Bedognè et al. (2006) | |
| www.mineralienatlas.de (n.d.) |
| found by FdW |
| Stalder et al. (1998) |
| Ref.: Stalder et al. (1973) | |
| Stalder et al. (1998) |
USA | |
| Betts (n.d.) |
| www.mineralsocal.org |
Sferlùn asbestos mine, Vallone del Cengiaccio, Lanzada, Sondrio Province, Lombardy, Italy