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www.mineralgallery.co.za Minerals A-E |
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Actinolite |
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Name
Actinolite
Chemistry
Ca2(Mg,Fe2+)5Si8O22(OH)2
Uses
sometimes used as a precious stone (facets, cabochons).
Color
green, grey-green, dark-green, emerald-green (smaragdite variety).
Hardness
5-6 (brittle)
Specific gravity
3.0 - 3.2
Crystal system:
monoclinic. The crystals usually in aggregates of long prismatic crystals. Actinolite sometimes occurs as massive or fibrous.
Accompanied by:
talc, chlorite, serpentine, epidote
Fracture
Uneven fracture
Luster
vitreous, silky
Cleavage
perfect on (110) Good cleavage
Streak
white
Similar to:
acmite, epidote, tourmaline, wollastonite
Tremolite and actinolite is the same mineral. The division between tremolite and actinolite is an arbitrary on, tremolite being the low-iron end and actinolite the iron-rich member.
Actinolite does not react to hydrochloric acid. Actinolite is common in low and medium-grade metamorphic rocks, actinolite generally occurring in schists produced by low- to medium grade metamorphism of basalt and dolerite or pelitic rocks.
Nephrite a dark green variety of 'jade' is usually an actinolite amphibole, and is carved into ornaments; asbestiform varieties of Tremolite worked to some extent; but are less valuable industrially than serpentine asbestos.
