1. ppl w/cleavage and opacite x5
1. ppl w/cleavage and opacite x5
2. xpl hornblende x5
3. xpl hornblende x5
4. ppl hornblende x10
5. ppl elongation east-west x5
6. ppl elongation north-south x5
7. xpl maximum birefringence x5
8. xpl inclined extinction x5
9. ppl pleochroism x5
10. xpl pleochreoism x5
11. xpl birefringence x5
12. ppl alkali north-south x5
13. ppl alkali east-west x5
14. xpl alkali max. birefring. x5
group amphibole
system monoclinic
formula Ca,Mg,Fe,Al silicate
optic biaxial neg / pos
Too-Vee 35 -130¡
relief.1 moderate to high pos
min. index 1.600 / 1.730
color brown, red, yellow
pleochroism yes yellow-green, brown
birefringence.1 0.014 - 0.034
cleavage yes amphibole cleavages {110} intersect at 56 and 124
elongation yes
extinction symmetrical, parallel
angle 10 - 35¡
alteration biotite, chlorite, or other Fe-Mg silicates
habit.1 equant, columnar, prismatic
occurence igneous (intermediate), metamorphic (medium to high grade, carbonate)
TwoV 1 2 3
relief 2 3
pleochroism.2 green, yellow, brown
birefringence 5 8 9 10 11 12
cleavage.2 {110} intersects at 56 and 124¡