Bytownite is a plagioclase feldspar whose composition falls between Na-rich albite and Ca-rich anorthite.
In thin section, plagioclase feldspar grains often look like they’re sprinkled with dirt (PPL) or tiny confetti (XPL). You can find the explanation on the plagioclase feldspar page.
Physical Properties |
|
| Chemical formula | (Ca,Na)(Si,Al)4O8 |
| Class | Tectosilicate 3D framework of linked tetrahedra |
| Crystal system | Triclinic |
| Habit | Tabular Massive Granular Frequently twinned from minerals.net |
| Color | Colorless Gray WhiteMay display labradorescence |
| Hardness | 7 |
| Specific gravity | 2.71 |
| Cleavage | Perfect {001}, good {010} |
| Fracture | Uneven |
| Luster | Vitreous |
| Transparency | Translucent to transparent |
| Streak | White |
Optical Properties |
|
| PPL | Colorless Non-pleochroic |
| XPL | 1st order gray |
| δ | 0.010 |
| after webmineral.com |
Bytownite in Hand Sample
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Bytownite in Thin Section
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