Mica: Properties, Facts and Photos

Mica is a group of minerals widely used in industry and everyday products, valued for their distinctive physical properties.

What is Mica?

Mica is a group of silicate minerals characterised by their thin, layered structure. Their crystal structure is unique because they split easily into fine, transparent, flexible sheets.

There are several types of mica, some of which include muscovite, lepidolite, biotite, and phlogopite.

Mica minerals, mostly found in metamorphic and igneous rocks, are known for their sparkling or shimmering/iridescent appearance.

A soft mineral that scratches easily, mica typically grades 2.5 to 3 on the Mohs scale of hardness. Because it's so delicate, it must be handled carefully. 

The most common type of mica, which is muscovite, is found in various colours, including white, silver and gold. Biotite is a black or brown variety, and phlogopite is golden-brown.

Mica minerals have several interesting properties, so they're widely used on an industrial scale. They're highly resistant to heat and can withstand high temperatures. They also have good insulating properties, so are used in the production of wires and cables.

Mica is used as a lubricant and protective coating in various applications, and in paints and coatings, it gives a shimmering metallic finish.

This group of minerals are valued for their unique physical properties and versatility.

Mica flakes are often used in cosmetics, skin care products, and body lotions because they add shimmer and iridescence. They also add lustre and sparkle and are used where brightening or glow is needed.Some of the world's largest mica deposits are found in one of India's poorest regions. It's also mined in Madagascar. Mines are often unregulated, and child labour is common. Because of these ethical concerns, our mica is sourced from Brazil, where it's mined primarily in the southeast of the country.

Lepidolite, another popular type of mica, is typically found in granite, pegmatite, and metamorphic rocks. Known for its lilac, pink or purplish colour, it's often found combined with quartz, feldspar and tourmaline.

Lepidolite is Earth's most common lithium-bearing mineral and one of the few that contains rubidium. Rubidium is a highly reactive, soft, silvery-white metallic element that must be handled carefully. Due to its reactivity, it tends to ignite spontaneously in air and reacts violently with water.

Rubidium is used to determine the age of rocks older than ten million years through a method known as rubidium-strontium dating.

Lithium is a key component in the production of batteries and other tech materials.

Some History of Mica Minerals

Mica minerals have a long history of use by humans and can be traced back many thousands of years.

It has been found in cave paintings from 40,000 to 10,000 BC.  

Some of the earliest recorded evidence of mica comes from ancient Indian texts, which describe its use in various applications, including cosmetics and jewellery. It has also been found in ancient Egyptian tombs.

The name comes from the Latin 'micare', meaning 'to shine'. This refers to mica's shimmering appearance.

Article Pictures

The lepidolite mica at the top of our article, and the single piece, are from our collection.

The second photo, which is muscovite mica, and the pop-up photo, which is tourmaline (elbaite), variety rubellite, are courtesy of Stan Celestian.