Crandallite
Mineral CaAl3(PO4)(PO3OH)(OH)6
About it
Pale, fine-grained masses and tiny crystals that form as other phosphates alter, notably as the yellowish rinds in Utah variscite nodules. Named for American geologist Milan Crandall.
- Type
- Mineral
- Group
- Phosphate, alunite supergroup
- Formula
- CaAl3(PO4)(PO3OH)(OH)6
- Hardness (Mohs)
- 4
- Specific gravity
- 2.78–2.92
- Streak
- white
- Lustre
- vitreous (glassy), dull
- Crystal system
- Trigonal
- Colours
- white, yellowish, light grey, brown
- Transparency
- translucent, opaque
- Cleavage and fracture
- good basal; uneven fracture
Typical values: real specimens vary. For more, see mindat.org.