Constituent
Name
Vitreous matrix
IMA name
Volcanic glass
Class
silicate mineral
Compound type
tektosilicate
Comments
Volcanic glass is classified as a mineraloid
Relevance
main - major
Arrangement
matrix
Formula
(Ca,Na,K,Mg,Mn,Fe2+,Fe3+,Ti,Al,...)SiO2
Chemical formula
(Ca,Na,K,Mg,Mn,Fe2+,Fe3+,Ti,Al,...)SiO2
Elemental formula
Si O2 Al0 Ti0 (Fe2+)0 (Fe3+)0 Mn0 Mg0 Ca0 Na0 K0
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
Si Silicon element 1 constituent element main
O Oxygen element 2 constituent element main
Al Aluminium element 0 constituent element main
Ti Titanium element 0 constituent element main
Fe2+ Iron(II) cation element 0 constituent element main
Fe3+ Iron(III) cation element 0 constituent element main
Mn Manganese element 0 constituent element main
Mg Magnesium element 0 constituent element main
Ca Calcium element 0 constituent element main
Na Sodium element 0 constituent element main
K Potassium element 0 constituent element main
Composition comments
contain a number of other minor elements
Oxides
Formula SiO2 Al2O3 TiO2 Fe2O3 MnO MgO CaO Na2O K2O
Mass fraction (%)
Oxides comments
SiO2: 64-80%, Al2O3: 10-15%, TiO2: 0.03-0.65%, Fe2O3 ...

Strunz

Class
silicates (09)
Division
unclassified silicates (09.H)
Family
Unclassified Silicate (09.HX)

Dana

Major class
silicates (VIII)
Class
unclassified silicates (78)
Type
Without Dana Classification Numbers (78.00)
Group
Unclassified Silicate (78.00.00)
Phase type
glassy
Crystal system
amorphous
Texture
glassy
Density
2.35 - 2.60 g/cm3
Refringence type
isotropic
Birefringence
none
Refraction index nα
1.45 - 1.55
Color
various
Diaphaneity
transparent to opaque
Luster
vitreous