Struvite
(NH4)MgPO4 • 6H2O [CNMNC approved formula]
Named after Heinrich Christian Gottfried Struve (1722-1851) of the Russian diplomatic service, Consul at Hamburg (Germany).
| IMA status : | Valid species (Pre-IMA 1845) Grandfathered |
| CLASSIFICATION | |
| Dana (8th edition) : |
40.01.01.01 |
| (40) Hydrated Phosphates | |
| (40.01) where A++ B++ (XO4) · x(H2O) | |
| (40.01.01) Struvite Group | |
| Nickel-Strunz (10th edition) : |
08.CH.40 |
| (08) Phosphates, Arsenates, Vanadates | |
| (08.C) Phosphates without Additional Anions, with H2O | |
| (08.CH) With large and medium-sized cations, RO4:H2O < 1:1 | |
| Crystal system: | Orthorhombic System |
| Point group (H-M): | mm2 — pyramidal |
| Unit cell: | a = 6.94Å, b = 11.2Å, c = 6.13Å |
| Crystal Habit: | Crystals short prismatic, thick tabular, equant, coffin-shaped, wedge-shaped, to 2 cm, distinctly hemimorphic |
| Twinning: | On {001} as twin and composition plane, with deep re-entrants. |
| Color: | Colorless, becomes white on dehydration |
| Diaphaneity: | Transparent to translucent |
| Luster: | Vitreous, dull when dehydrated |
| Hardness (Mohs): | 2 |
| Measured Density: | 1.711 g/cm3 |
| Cleavage: | 2; {001} good, {100} poor |
| Tenacity: | Brittle |
| Fracture: | Subconchoidal to uneven |
| Streak: | White |
| Geologic Setting: | In peaty earth intermixed with cattle dung (Hamburg, Germany); typically formed in bird or bat guano in caves and surface deposits. |
| Mineral Association: | Newberyite, hannayite, brushite, stercorite |
| Synonyms/varieties: | Guanite, Struveite |
| Other Properties: | Piezoelectric. Pyroelectric. H2O Soluble. Gemstone Extremely Rare. BioMineral. |
| Comments: | Slightly dissolves in H2O. Dehydrates in dry, warm air. |
Struvite scalingOrigin: ?
Sample size 3 x 1.8 x 1 cm
Sample owner: Ray Frost
Photo: Theo Kloprogge
(zoom-in of above)
Origin: ?Sample size: 4 x 3.5 x 2 cm
Sample owner: Ray Frost
Photo: Theo Kloprogge
(zoom-in of above)