Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Mg$	Magnesium	element	0 - 1.5		constituent element	main
	$Mn^{2+}$	Manganese(II) cation	element	1.5 - 3		constituent element	main
	$Si$	Silicon	element	2		constituent element	main
	$O$	Oxygen	element	9		constituent element	main
	$H$	Hydrogen	element	4		constituent element	main

Composition comments

Common substitution: Zn, Fe^{2+} substituting Mn^{2+} and Mg, As substituting Si, Cl substituting OH (sometimes in the formula: $(Mn^{2+},Mg,Zn,Fe^{2+})_3(Si,As)_2O_5(OH,Cl)_4$) - Common impurities: Al, Ca, F

Chemical functions

	Function	Number
	$(OH)^-$	4

Chemical bonds

	Bond	Number
	$O^--H$	1

Oxides

Formula	$MnO$	$MgO$	$SiO_{2}$	$H_{2}O$
Mass fraction (%)

Strunz

Class

silicates (09)

Division

phyllosilicate (09.E)

Family

Phyllosilicates with kaolinite layers (09.ED)

Code

09.ED.15

Dana

Major class

silicates (VIII)

Class

phyllosilicate sheets of six-membered rings (71)

Type

with 1:1 layers (71.01)

Group

Serpentine group (Lizardite subgroup) (71.01.02b)

Code

71.01.02b.01

Phase type

crystalline

Crystal system

monoclinic

Crystal class

prismatic

Crystal class symbol

2/m (C2h)

Crystal spacegroup

C2/m

Refringence type

biaxial

Refringence sign

negative

Birefringence

0.026 - 0.030

Refraction index $n_{\alpha}$

1.606 - 1.62

Refraction index $n_{\beta}$

1.632 - 1.65

Refraction index $n_{\gamma}$

1.632 - 1.65

Dispersion V

weak

Pure color

yellow

Color

yellow, reddish brown, greenish brown, orange brown

Diaphaneity

transparent to translucent

Luster

vitreous

Links

• Wikipedia
• Webmineral database
• Mindat
• Handbook of Mineralogy (Min. Soc. Am)