A rainbow of fluorite

Much like quartz, fluorite (CaF2) comes in an array of colours.

Most people are familiar with green and purple fluorite. But did you know it can also be yellow, blue, pink, colourless and even striped with a mix of colours (known as rainbow fluorite).

The different colours in fluorite are the result of chemical impurities and natural irradiation.

The primary way fluorite is formed is through hydrothermal processes.

Fluorite occurs when hydrothermal water flows through fractures and cavities in calcium & fluorine-rich rock deposits. When the calcium & fluorine-rich solution cool and react with other minerals, they precipitate fluorite crystals.

In the 1800s, fluorite was the first mineral to fluoresce under ultra-violet light. The term ‘Fluorescence’ is actually named after the mineral fluorite.

Surprisingly, Not all fluorite crystals fluoresce. This is because the activators that causes this fluorescence are trace elements &/or organic material trapped in the fluorite crystal structure.

Many specimens of fluorite have a strong enough fluorescence that you can hold them in sunlight & then move them into shade and see a color change.

Fluorite crystals are commonly cubic or octahedrons, but others forms do occur.

Fluorite is one of the main sources of fluorine.

Common uses of fluorine include fluorescent lighting and as an additive in municipal water to strengthen teeth.

Both fluorite and fluorine have many other uses.

The variety of colours (including natural striping) make fluorite an attractive mineral for jewelry (mostly cabochons & beads) & carvings.

My personal favorite type of fluorite is rainbow fluorite. Isn’t it beautiful?!

In selling my jewelry, I have noticed that it is common for customers to mistake purple fluorite for amethyst. In my next blog, I will outline the differences between these minerals so you can identify your purple gemstone jewelry.