Whiteite

Formula: Ca(Fe,Mn)Mg₂Al₂(PO₄)₄(OH)₂.8H₂O

Origin of name: for John S. White Jr. (1933-), former editor of the Mineralogical Record and professional curator of minerals and gems

Crystal system: Monoclinic

Crystal class: 2/m

Twinning: universal on {001}

Unit cell: a = 14.9, b = 6.98, c = 10.13, β = 113.12° (CaFeMg), a = 14.842, b = 6.976, c = 10.109, β = 112.59° (CaMnMg), a = 14.99, b = 6.96, c = 10.14, β = 113.32° (MnFeMg)

Colour: Tan to yellowish (CaFeMg), greenish yellow, yellow, light lilac, pink (CaMnMg), chocolate brown (MnFeMg)

Diaphaneity: Transparent

Luster: Vitreous to dull

Habit: crystals prismatic to 2 cm, tabular, aggregates

Hardness: About 3.5-4

Specific gravity: 2.58 (CaFeMg), 2.63 (CaMnMg), 2.63-2.67 (MnFeMg)

Cleavage: 1, perfect

Tenacity: 

Streak: White (CaFeMg and CaMnMg), brownish white (MnFeMg)

Synonyms/varieties:

Comments: three distinct species with the extensions -(CaFeMg)m -(CaMnMg) and -(MnFeMg) indicating the predominant cations in the first three positions in the formula