Ottrelite
Ottrelite
General
Category	Nesosilicate
Formula (repeating unit)	(Mn,Fe,Mg)2Al4Si2O10(OH)4
Strunz classification	09.AF.85
Identification
Formula mass	490.11
Color	Pistachio green
Crystal habit	Granular
Twinning	Polysynthetic, {001}
Cleavage	{001} perfect; {110} likely
Mohs scale hardness	6–7
Luster	Vitreous to nearly adamantine on cleavages
Streak	Greenish, grayish
Diaphaneity	Translucent
Specific gravity	3.50
Density	3.52
Dispersion	r > v, strong
References	[1][2][3]

Ottrelite is a form of chloritoid. Its empirical formula is (Mn,Fe,Mg)₂Al₄Si₂O₁₀(OH)₄.

See also[edit]

• List of minerals

References[edit]

External links[edit]

Media related to Ottrélite at Wikimedia Commons