What is hornblende rock?
Hornblende is a complex inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common in igneous and metamorphic rocks.
What is hornblende used for?
Its primary use might be as a mineral specimen. However, hornblende is the most abundant mineral in a rock known as amphibolite which has a large number of uses. It is crushed and used for highway construction and as railroad ballast. It is cut for use as dimension stone.
How is hornblende rock formed?
It forms in a number of gneissic rocks formed at moderate grades of metamorphism. Amphibolites are common metamorphic rocks consisting in large part of dark amphibole. Igneous and metamorphic rocks containing hornblende are widespread throughout Wisconsin’s Precambrian shield.
Where is hornblende found?
Hornblende is commonly found in metamorphic rocks such as schists and gneisses, and igneous rocks such as diorites and dacites.
What is hornblende made of?
Hornblende is a inosilicate amphibole minerals, which are two type hornblende minerals. They are ferrohornblende and magnesiohornblende. They are an isomorphous mixture of three molecules; a calcium-iron-magnesium silicate, an aluminium-iron-magnesium silicate, and an iron-magnesium silicate.
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 are special properties of hornblende?
Hornblende Physical Properties
| Color | Usually black, dark green, dark brown |
|---|---|
| Streak | White, colorless – (brittle, often leaves cleavage debris behind instead of a streak) |
| Luster | Vitreous |
| Cleavage | Two directions intersecting at 124 and 56 degrees |
| Diaphaneity | Translucent to nearly opaque |
What type of mineral is 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.