| Huntite | |
|---|---|
 | |
| General | |
| Category | Carbonate mineral |
| Formula (repeating unit) | Mg3Ca(CO3)4 |
| IMA symbol | Hun[1] |
| Strunz classification | 5.AB.25 |
| Dana classification | 14.04.03.01 |
| Crystal system | Trigonal |
| Crystal class | Trapezohedral (32) H-M symbol: (3 2) |
| Space group | R32 |
| Unit cell | a = 9.505 Å, c = 7.821 Å; Z = 3 |
| Identification | |
| Formula mass | 353 g/mol |
| Color | White, lemon white |
| Crystal habit | Platy crystals; compact chalklike masses |
| Fracture | Subconchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 1–2 |
| Luster | Earthy (dull) |
| Streak | White |
| Diaphaneity | Translucent |
| Specific gravity | 2.696 |
| Optical properties | Uniaxial (–) |
| Refractive index | nω = 1.622 nε = 1.615 |
| References | [2][3][4] |
Huntite is a carbonate mineral with the chemical formula Mg3Ca(CO3)4.[4] Huntite crystallizes in the trigonal system and typically occurs as platy crystals and powdery masses. For most of recorded history its main use was as a white pigment.[5][6] Today the most common industrial use of huntite is as a natural mixture with hydromagnesite as a flame retardant or fire retardant additive for polymers.
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Handbook of Mineralogy: Huntite
- ^ Huntite on Mindat.org
- ^ a b Huntite on Webmineral
- ^ John Clarke, "Two Aboriginal Rock Art Pigments from Western Australia: Their Properties, Use, and Durability." Studies in Conservation, Volume 21, Issue 3 (1976) pp. 134–142 https://doi.org/10.1179/sic.1976.023
- ^ Richard Parkinson, The Painted Tomb-Chapel of Nebamun: Masterpiece of Ancient Egyptian Art in the British Museum (The British Museum Press: London, 2008) page 50