Huntite
Huntite is a carbonate mineral with the chemical formula Mg3Ca(CO3)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. 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.
| Huntite | |
|---|---|
| General | |
| Category | Carbonate mineral |
| Formula (repeating unit) | Mg3Ca(CO3)4 |
| IMA symbol | Hun |
| 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 | |
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.