Ardealite
Ca2(PO3OH)(SO4) • 4H2O [CNMNC approved formula]
Named from "Ardeal," the old Romanian name for Transylvania, wherein lies the type locality.
| IMA status : | Valid species (Pre-IMA 1932) Grandfathered |
| CLASSIFICATION | |
| Dana (8th edition) : |
43.01.01.01 |
| (43) Compound Phosphates | |
| (43.01) (Acid with Compound Anions.) | |
| (43.01.01) | |
| Nickel-Strunz (10th edition) : |
08.CJ.50 |
| (08) Phosphates, Arsenates, Vanadates | |
| (08.C) Phosphates without Additional Anions, with H2O | |
| (08.CJ) With only large cations | |
| Crystal system: | Monoclinic System |
| Point group (H-M): | m — domatic |
| Unit cell: | a = 5.721 Å, b = 30.992 Å, c = 6.250 Å, b = 117.26° |
| Crystal Habit: | Very fine-grained powdery masses and crusts |
| Color: | Pale yellow, yellow, brownish yellow, colorless |
| Diaphaneity: | Semitransparent |
| Hardness (Mohs): | 1 - 1.5 |
| Measured Density: | 2.34 g/cm3 |
| Streak: | White |
| Geologic Setting: | In limestone caves, as an early stage of the breakdown of bat guano, in reaction with calcite. |
| Mineral Association: | Brushite, gypsum, carbonate-hydroxylapatite, newberyite, taranakite |
| Other Properties: | BioMineral. |
Origin: Moorba Cave, Jurien Bay, Western Australia, AustraliaSample size: Tan coloured powder in micromount box.
Photo: Tom Loomis