Mineral - Aegirine
Aegirine
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
NaFe[Si₂O₆]
Unit Cell
a=9.66 b=8.80 c=5.29 β=107° Z=4
Physical Properties
Hardness
6
Streak
grayyellow gray
Density
Normal (2-3,5)
Cleavage
good after {110}
Fracture
uneven
Tenacity
Brittle
Optical Properties
Color
blackgreen
Birefringence
0.037-0.061
Luster
Vitreous
Transparency
translucent,
opaque
Pleochroism
Geomineralogical Properties
Crystal System
monoclinic
Point Group
monoclinic-prismatic - 2/m
Space Group
C2/c (15)
Habit
acicular, prismatic
Formation
Under agpaitic to peralkaline conditions in differentiated syenitic and phonolitic magmas as well as in their pegmatites and hydrothermal fissure fillings, whereby its formation is favored by high Na and Fe³⁺ activity and low Ca contents
Paragenesis
Twinning
Nach {100} und {010}
Rarity
Common
Synonyms
Aegirine, Acmite, Acnite, Agirine, Aegyrine, Aegyrite, Aegerite
Composition
Elements
Mass
SiO₂
51.35
TiO₂
1.10
AlsO₃
2.15
Fe₂O₃
28.66
FeO
2.24
MgO
0.10
CaO
1.25
Na₂O
12.66
K₂O
0.15
H₂₀
0.29
Brazil (Dana 1892)
Groups and Members
Pyroxene-Group
Clinopyroxene Subgroup
Name and first record : Named after the Norse god of the seas, "Aegir," due to its first record. First described by PH Ström (1821) from Rundemyr, Norway
Chemistry : Aegirine is a clinopyroxene which represents chain silicates (inosilicates).
Synonyms : Acmite, Acnite, Aegirite
Varieties : Fedorovite, Urbankite, Titanium Aegirine, Vanadium Aegirine
Abbreviation : Aeg
literature
Dana, J. D., & Dana, E. S. (1892). The system of mineralogy of James Dwight Dana, 1837-1868: descriptive mineralogy . J. Wiley & sons.