|Mineral class||Silicates : Tektosilicates : Feldspar group|
|Chemical formula||(Ca,Na)(Si,Al)4O8 (50-30% Na, 50-70% Ca)|
|Habitus||Tabular to prismatic crystals. Commonly with polysynthetic twinning. The twinning is very easy to see in labradorite. Often as granular or compact masses.|
|Cleavage||Perfect in one direction, good in another with 90 degrees angle. Fracture uneven to conchoidal.|
|Color||White, bluish to dark gray. In some directions it shows a rich play of colors|
|Luster||Vitreous to pearly. Transparent to translucent.|
|Description||Often quarried for jewelry and monumental stone.|
|Occurance||A major part in rocks as diabas basalt and gabbro, more rarely in granitic rocks.|
|Notes|| Look for the color play on broken surfaces.|
Soluble in acid when powdered.
|Locations|| A common mineral. |
| To silicate index.
|| Mineral group index.
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