Secondary names

Olivine series

	Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Fe^{2+}$	Iron(II) cation	element	0 - 2		constituent element	main
	$Mg$	Magnesium	element	0 - 2		constituent element	main
	$Si$	Silicon	element	1		constituent element	main
	$O$	Oxygen	element	4		constituent element	main

Composition comments

perfect solid solution - Common impurities: Mn, Ni

Chemical functions

	Function	Number
	$(SiO_4)^{4-}$	1

Chemical bonds

	Bond	Number
	$\geq Si-O^-$	4

Oxides comments

FeO de 0 à 70.5%, MgO de 0 à 57.3%, SiO2 de 29.5 à 42.7%

Strunz

Class

silicates (09)

Division

nesosilicate (09.A)

Family

without additional anions; cations in octahedral [6] coordination (09.AC)

Code

09.AC.05

Dana

Major class

silicates (VIII)

Class

nesosilicate insular SiO4 groups only (51)

Type

with all cations in octahedral [6] coordination (51.03)

Group

Olivine group (51.03.01)

Code

51.03.01.00

End-members

• Fayalite
• Forsterite

Members

• Fayalite (Mg = 0-10%, Fe = 100-90%)
• Ferrohortonolite (Mg = 10-30%, Fe = 90-70%)
• Hortonolite (Mg = 30-50%, Fe = 70-50%)
• Hyalosiderite (Mg = 50-70%, Fe = 50-30%)
• Chrysolite (Olivine) (Mg = 70-90%, Fe = 30-10%)
• Forsterite (Mg = 90-100%, Fe = 10-0%)

Phase type

crystalline

Crystal system

orthorhombic

Crystal class

dipyramidal

Crystal class symbol

mmm (D2h)

Crystal spacegroup

Pnma

Refringence type

biaxial

Refringence sign

negative

Birefringence

0.0330 - 0.0510

Refraction index $n_{\alpha}$

1.636 - 1.824

Refraction index $n_{\beta}$

1.65 - 1.864

Refraction index $n_{\gamma}$

1.669 - 1.875

Pure color

colorless

Color

colorless, brown, green, yellow, yellow green, white, black

Diaphaneity

transparent to translucent

Luster

vitreous

Links

• Wikipedia
• Webmineral database
• Mindat