Hornblende

Hornblende is actually the name given to a series of minerals that are rather difficult to distinguish by ordinary means. The iron, magnesium and aluminum ions can freely substitute for each other and form what have been distinguished as seperate minerals. The minerals are given the names Magnesio-hornblende, Ferrohornblende, Alumino-ferro-hornblende and Alumino-magnesio-hornblende. These minerals are obviously named for their chemistries although there is little to distinguish them in the field. The iron rich members of the series are more darker black and less likely to be translucent.

Hornblende is not often a collection mineral because good crystals are somewhat difficult to find even though the mineral is widespread. It is almost always opaque and black and not very attractive. However a few specimens are extraordinary and make for valuable specimens. Some crystals can grow to a fairly large size of several feet long and nearly a foot across. Other specimens of hornblende can be acicular clusters or needle thin crystal aggregates. Many times a specimen of a more valuable mineral will be accented by the opaque black crystals of hornblende.