Tenacity
Very brittle
-
Solubility
insoluble
-
Durability
-
-
Specific Gravity
3.30-3.402.74-2.76
1
7.18
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Fracture
Conchoidal
Uneven
Cleavage
{010} perfect, {110} distinct, {100} in traces
{010} Perfect, {001} Distinct
Mohs Hardness
6.5-73.5-4
2
10
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Chemical Composition
AlO(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Fe3+ PO 4 · 2H 2OAnthony et al , Handbook of Mineralogy (2001)