Constituent
- Name
- Akermanite
- IMA name
- Akermanite
- Class
- silicate mineral
- Compound type
- sorosilicate
- Relevance
- main - major
- Arrangement
- single phase
- Mass fraction
- 1.0
- Formula
- $Ca_2Mg(Si_2O_7)$
- Chemical formula
- Ca2MgSi2O7
- Elemental formula
- Mg0.977 Ca2.005 Si2.007 O7 Na0.001 K0.001 Ti0.001 Fe0.001
- Isotope mixture type
- terrestrial abundance
- Oxides
-
Formula $Na_{2}O$ $K_{2}O$ $FeO$ $SiO_{2}$ $TiO_{2}$ $MgO$ $CaO$ $NiO$ Mass fraction (%) 0.01 0.01 0.02 44.4 0.02 14.49 41.4 0.01
Strunz
- Class
- silicates (09)
- Division
- sorosilicate (09.B)
- Family
- Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater coordination (09.BB)
- Code
- 09.BB.10
Dana
- Major class
- silicates (VIII)
- Class
- sorosilicate Si2O7 groups, generally with no additional anions (55)
- Type
- with cations in [8] and lower coordination (55.04)
- Group
- Melilite group (55.04.01)
- Code
- 55.04.01.01
- Phase type
- crystalline
- Crystal system
- tetragonal
- Crystal class
- scalenohedral
- Crystal class symbol
- -42m (D2d)
- Crystal spacegroup
- P-42(1)m
- Molar mass
- 272.62 $g/mol$
- Density
- 2.944 (calc.: 2.94) $g/cm^3$
- Refringence type
- uniaxial
- Refringence sign
- positive
- Birefringence
- 0.008
- Refraction index $n_{\alpha}$
- 1.632
- Refraction index $n_{\beta}$
- 1.640
- Color
- colorless, grayish, green, brown.
- Diaphaneity
- transparent to translucent
- Luster
- vitreous