Silicates Minerals

Tremolite is a silicate mineral and member of the amphibole group. Chemical formula is Ca2(Mg5.0-4.5Fe2+0.0-0.5)Si8O22(OH)2. A calcium magnesium silicate, tremolite forms a solid-solution series with ferroactinolite, where iron substitutes in increasing amounts for magnesium.

A light mica, lepidolite is Earth’s most common lithium-bearing mineral. Its name is derived from two Greek words: lepidos, which means “scale,” and lithos, which means “stone.” Although typically pale lilac, specimens can also be colorless, violet, pale yellow, or gray. Lepidolite crystals may appear pseudohexagonal. The mineral is also found as botryoidal or kidneylike masses and fine- to coarse-grained, interlocking plates. Its perfect cleavage yields thin, flexible sheets. Lepidolite occurs in granitic pegmatites, where it is associated with other lithium minerals, such as beryl and topaz. The mineral is economically important as a major source of lithium, which is used to make glass and enamels. It is also a major source of the rare alkali metals rubidium and cesium.

Nepheline is the most common feldspathoid mineral in the world, its name from the Greek word nephele, which means “cloud” a reference to the fact that the mineral becomes cloudy or milky in strong acids. Specimens are usually white in color, often with a yellowish or grayish tint.

Diopside is a member of pyroxene group mineral with formula is MgCaSi2O6. Specimens can be colorless but are more often bottle green, brownish green, or light green in color. It has two distinct prismatic cleavages at 87 and 93° typical of the pyroxene series. Diopside occurs in the form of equant to prismatic crystals that are usually nearly square in section.

The Glaucophane mineral is named after two Greek words: glaukos, which means “bluish green”; and phainesthai, which means “to appear.” Specimens can be gray, lavender blue, or bluish black. Crystals are slender, often lathlike prisms, with lengthwise striations. Twinning is common. Glaucophane can also be massive, fibrous, or granular. When iron replaces the magnesium in its structure, it is known as ferroglaucophane. Glaucophane occurs in schists formed by high-pressure metamorphism of sodium-rich sediments at low temperatures (up to 400°F/200°C) or by the introduction of sodium into the process. Glaucophane is often accompanied by jadeite, epidote, almandine, and chlorite. It is one of the minerals that are referred to as asbestos. Glaucophane and its associated minerals are known as the glaucophane metamorphic facies. The presence of these minerals indicates the range of temperatures and pressures under which metamorphism occurs.

Tourmaline is a fascinating gemstone that is known for its wide range of colors and unique properties. It is a crystalline mineral composed of...

Jasper is a type of mineral that is primarily composed of silica, with other trace elements and impurities giving it its unique colors and...

Andalusite is a rock forming minerals and is an aluminium nesosilicate minerals with the chemical formula Al2SiO5.At higher temperatures and pressures, andalusite may convert to sillimanite.andalusite is an aluminosilicate index mineral, providing clues to depth and pressures involved in producing the host rock.

Wollastonite is a group of innosilicate mineral, formula is CaSiO3 that may inlude small amount of magnesium, manganese and iron substituting for calcium. A...

Onyx is a type of chalcedony, which is a microcrystalline form of quartz. It is a banded variety of chalcedony that forms in concentric...

Rose quartz is a pink-colored variety of the mineral quartz (SiO2), often considered one of the most popular and recognizable gemstones. It derives its...

Illite is a type of clay mineral that belongs to the group of non-expanding or non-swelling phyllosilicate minerals. It is a common constituent of...