Constituent
Name
Vitreous matrix
IMA name
Volcanic glass
Class
silicate mineral
Compound type
tektosilicate
Comments
Volcanic glass is classified as a mineraloid
Constituent abundance in material
Relevance
main - major
Arrangement
matrix
Chemical composition
Formula
$(Ca,Na,K,Mg,Mn,Fe^{2+},Fe^{3+},Ti,Al,...)SiO_2$
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
$Fe^{2+}$ Iron(II) cation element 0 constituent element main
$Fe^{3+}$ 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 $SiO_{2}$ $Al_{2}O_{3}$ $TiO_{2}$ $Fe_{2}O_{3}$ $MnO$ $MgO$ $CaO$ $Na_{2}O$ $K_{2}O$
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)
Code
N/A

Dana

Major class
silicates (VIII)
Class
unclassified silicates (78)
Type
Without Dana Classification Numbers (78.00)
Group
N/A
Code
N/A
Phase type
glassy
Crystal system
amorphous
Crystal class
N/A
Crystal class symbol
N/A
Crystal spacegroup
N/A
Texture
glassy
Density
2.35 - 2.60 $g/cm^3$
Refringence type
isotropic
Birefringence
none
Refraction index $n_{\alpha}$
1.45 - 1.55
Color
various
Diaphaneity
transparent to opaque
Luster
vitreous