What is the chemical composition of hornblende?

What is the chemical composition of hornblende?

hornblende, calcium-rich amphibole mineral that is monoclinic in crystal structure. Hornblende’s generalized chemical formula is (Ca,Na)2(Mg,Fe,Al)5(Al,Si)8O22 (OH)2.

What is the luster of almandine?

VitreousAlmandine / Luster

How is almandine formed?

Almandine is often embedded in a mica schists, and forms very nice matrix pieces with perfectly formed symmetrical crystals. The schist matrix often breaks up due to weathering, resulting in the Almandine crystals breaking loose into individual, perfectly formed floater crystals which may be quite large.

What is the chemical composition of almandine?

Almandine is one end-member of a mineral solid solution series, with the other end member being the garnet pyrope. The almandine crystal formula is: Fe3Al2(SiO4)3. Magnesium substitutes for the iron with increasingly pyrope-rich composition.

What color is hornblende?

Color – Hornblende is generally pleochroic in shades of brown and green, less commonly yellow or red-brown. Concentric or patchy color zonation may be present. Actinolite is similar but colors are restricted to greens. Cleavage – Amphiboles have diagnostic 60o-120o cleavage angles when viewed in end section.

What type of silicate is almandine?

Almandine, Fe2+Al2(SiO4)3, is classified as a garnet Nesosilicate, of the Pyralspite Group.

What Colour is almandine garnet?

Deep red
Almandine Garnet Information

What type of rock is almandine?

almandine, either of two semiprecious gemstones: a violet-coloured variety of ruby spinel (q.v.) or iron aluminum garnet, which is most abundant of the garnets.

What is the luster of hornblende?

Vitreous to dull