General Information:
Chemical Formula:Ca12Al2Si18O33(OH)36
Composition:(Molecular Weight = 2,180.68 gm)Calcium 22.05 %
CaAluminum 2.47 %
AlSilicon 23.18 %
SiHydrogen 1.66 %
H Oxygen 50.62 %
O Empirical Formula: Ca12Al2Si18O33(OH)36
Environment:In vesicles or fracutes in dolorites or other basic igneous rocks.
IMA Status:Approved IMA 1961
Locality:Portree, Isle of Skye, Scotland.
Name Origin:Named from the Gaelic "tacharan," a changeling, because on standing in air the mineral breaks down to form other compounds (not noticed by later investigators).
Physical Properties: Color:white.
Density:2.21 - 2.36, Average = 2.28
Habits:Cryptocrystalline - Occurs as crystals too small to distinguish with the naked eye., ,
Hardness:5 - Apatite
Luster:Earthy (Dull)
Streak:white
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