Major Minerals
"Mineral occurences vary. Some
are minor, others are major
minerals."
Here are descriptions of some of the commonest ones. These can often be called by these names to simplify things, but all are actually groups of mineras - yes, there are even different kinds of quartz.
Quartz Mineral
Quartz is one of the absolutely most common minerals on the Earth. It is found in all types of rocks and is very abundant in most sands and hydrothermal veins. It can be massive or form crystals. It can come in many different colours such as transparent, white, pink, purple, brown and reddish brown.
Mineral Mica
Mica is a group of shiny, layered minerals such as biotite and muscovite. They very seldom occur in the amounts like on the photo here. Most often they don't even make 10% of a rock's matrix, but are still easily visible and often i large crystals. They are very soft minerals, which easily break along layers.
Feldspar Mineral
Feldspar is also a very common mineral. It is the most common mineral in the Earth's crust, and it is an essential mineral in most igneous rocks. There are two major groups within the group of feldspars - plagioclase and alkali feldspars, in a solid solution with three end members: K-feldspar, albite and anorthite.
Pyroxene
Pyroxenes are a group of common, black or dark green mafic, ferromagnetic minerals with elongate crystals rich is iron and magnesuim. They are also common minerals and always occur in basalts at mid-ocean ridges. They include orthopyroxene, pigeonite, hedenbergite, diopside, jadeite, augite, aegerine, spodumene and omphacite.
Amphibole
Amphiboles are minerals very similar to pyroxenes. Also dark in colour, rich in iron and magnesium (mafic), and occur in elongate, dark crystals. They are more common than pyroxenes and typically black or dark brown. They include hornblende, anthophyllite, tremolite, cummingtonite, gerdite, glaucophane and riebeckite.
