Nesosilicates

Nesosilicates

 

Zircon’s name comes from the Arabic “car”, gold, plus “gun” colored, referring to one of the many colors that the mineral may display. It is found in most igneous rocks as small crystals and as alluvial grains due to its high hardness. When crystals are large enough, it is used as a gemstone.

 

The vitreous luster of this gem mineral is what distinguishes it from quartz. In the 1940s, a 596-pound crystal was found in Minas Gerais, Brazil. The name is derived from Topazion, an island in the Red Sea.

 

Formed during metamorphism of aluminum-rich rocks, this mineral commonly occurs as twined crystals earning it the name “fairy crosses”. Its name is derived from the Greek word meaning “cross,” in allusion to its cruciform twins.

 

Discovered in 1824, this mineral was named in honor of Benjamin Silliman (1779-1864), a professor of chemistry and geology at Yale University. It is a comparatively rare mineral found in high-grade metamorphic rocks.

 

Found in granite pegmatites and schists, this mineral was named in 1833 by Nordenskiold from the Greek word for “deceiver,” in allusion to its being mistaken for quartz. It is occasionally cut as a gemstone.

 

A common rock-forming mineral, olivine is found in mafic igneous rocks. The rock, dunite, is made up almost wholly of olivine. The transparent gem variety is known as peridot. It derives its name from the usual olive-green color.

 

This mineral is easily identified by its blue, pearly, bladed crystals. It is found in metamorphic environments, often with garnet, staurolite, and corundum. It was named in 1789 by A.G. Werner from the Greek word kyanos meaning blue.

 

This is a group of minerals with the same structure. It commonly forms dodecahedrons with the color of the garnet varying with composition. For example, pyrope is red due to Ca and Fe; uvarovite is green due to the presence of calcium-chromium. Its name is derived from the Latin granatus, meaning “like a grain.”

 

Named from the Greek word meaning “to divide,” in reference to the granular texture, this mineral was discovered in 1806 in Norway. It is characterized by its glassy luster, pale green color, and its crystals with many faces.

 

Discovered in 1817, this mineral was named from the Greek word for “grain,” in allusion to it occurring in isolated grains. It is commonly found in contact metamorphic rocks and is characterized by its light yellow to red color.