Secondary names

Leonhardtite

IMA Code

Ske

	Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Mg^{2+}$	Magnesium(II) cation	element	1		constituent cation	main
	$(SO_4)^{2-}$	Sulfate anion	chemical function	1		anionic radical	main
	$H_2O$	Water	molecule	4		hydration	main

Composition comments

Soluble in water. Common impurities: Fe

Chemical functions

	Function	Number
	$(SO_4)^{2-}$	1
	$R-OH$	2

Chemical bonds

	Bond	Number
	$\cdot Mg^{2+} \cdot O^{-}-$	2
	$-O \dots H-$	8
	$-O-H$	2
	$\dddot - \dddot - \dddot - S \dddot - O^{-1/2}$	4

Oxides

Formula	$MgO$	$SO_{3}$	$H_{2}O$
Mass fraction (%)	20.94	41.61	37.45

Strunz

Class

sulfates - chromates - molybdates - tungstates (07)

Division

sulfates (selenates, etc.) without additional anions, with H2O (07.C)

Family

with only medium-sized cations (07.CB)

Code

07.CB.15

Dana

Major class

sulfates, chromates, selenates (VI)

Class

hydrated acid and sulfates (29)

Type

where AXO4.x(H2O) (29.06)

Group

Rozenite group (Tetrahydrates, monoclinic) (29.06.06)

Code

29.06.06.02

Phase type

crystalline

Crystal system

monoclinic

Crystal class

prismatic

Crystal class symbol

2/m (C2h)

Crystal spacegroup

P2(1)/m

Refringence type

biaxial

Refringence sign

positive

Birefringence

0.007

Refraction index $n_{\alpha}$

1.49

Refraction index $n_{\beta}$

1.491

Refraction index $n_{\gamma}$

1.497

Dispersion V

none

Pure color

colorless

Color

colorless, white, yellowish, greenish

Diaphaneity

transparent to opaque

Luster

earthy

Links

• Wikipedia: Starkeyite
• SaltWiki: Starkeyite
• Webmineral: Starkeyite
• Mindat: Starkeyite
• Handbook of Mineralogy (Min. Soc. Am): Starkeyite