Hexagonal

Hexagonal

 

This mineral is confined almost exclusively to the zinc deposits in Franklin, New Jersey. It is distinguished chiefly by its red color and orange-yellow streak. An ore of zinc, its name is in allusion to the high zinc content.

 

Discovered in 1772 in the Czech Republic, this mineral is named from its elemental composition containing uranium. It occurs in granitic and syenitic pegmatites, as colloform crusts in high temperature hydrothermal veins, and in quartz-pebble conglomerates. It is the chief ore of uranium.

 

A common accessory mineral in igneous rocks, ilmenite was named after its type locality in the Ilmen Mountains in Russia. It is a major source of titanium, which is used principally in the manufacture of paint and as a structural material because of its high strength-to-weight ratio.

 

This mineral comes in many forms, both metallic and nonmetallic, such as: botryoidal (known as kidney ore), micaceous and foliated known as specular; and earthy, oolitic, iron roses. But regardless of its form, it can always be identified by its characteristic red streak. It is widely distributed and forms the most abundant and important ore of iron. The name is derived from a Greek word meaning “blood”, in allusion to the color of the powdered mineral.

 

This mineral’s crystals commonly occur as barrel shapes with deep horizontal striations. It is common as an accessory mineral in silica poor rocks, and is frequently found in detrital soil and stream sands due to its hardness. The red gem variety is called ruby, one of the most valuable of gems. The blue gem variety is called sapphire.

 

Discovered in 1824, this mineral was named after Archibald Bruce (1777-1818), an early American mineralogist, who first described the species. It can be identified by its foliated nature, light color, and pearly luster on cleavage face. It can be distinguished from mica by being inelastic.

 

Graphite was named from the Greek “graphein” meaning ‘to write’ by German chemist and mineralogist A.G. Werner in 1789. It occurs most commonly in metamorphic rocks and is used as a lubricant, the manufacture of refractory crucibles and of course, pencils. It is easily distinguished by its greasy feel and the dark marks it leaves on hands.