Fluorite Gemstones – Properties, Origins, Treatments and Buying Guide

Fluorite is one of the most visually striking gemstones, prized for its wide range of vibrant colours and strong clarity. Unlike stones that rely on deep saturation, fluorite is valued for its purity of colour, fluorescence, and natural geometric crystal forms.

In this guide we examine fluorite from a professional gemmological and commercial perspective, covering its physical properties, crystal structure, treatments, origins and how to identify fine-quality stones.

Fluorite is a colourful mineral composed of calcium fluoride (CaF₂), forming in cubic crystals with excellent transparency. It occurs in veins, hydrothermal deposits, and sedimentary rocks. Unlike many gemstones, fluorite frequently forms large, perfectly shaped octahedral or cubic crystals suitable for collectors and jewellery alike.

Fluorite has the chemical formula:

CaF₂

This means it is composed primarily of:

Calcium
Fluorine

High-quality fluorite is transparent and free of significant inclusions, allowing for intense internal colour display and optical effects such as fluorescence.

Fluorite belongs to the halide mineral family.

Its crystal system is isometric (cubic), often forming perfect cubes or octahedra, which enhances its visual appeal in jewellery and collectors’ specimens.

Fluorite combines vivid colour, clarity, and excellent optical effects such as fluorescence and color zoning, making it highly desirable for decorative and collector pieces.

Lustre
Vitreous, giving a bright, glass-like shine.

Transparency
Transparent to translucent; gem-quality stones are highly transparent.

Refractive index
1.434 – 1.438, providing gentle brilliance and clear internal reflection.

Specific gravity
3.0 – 3.2, typical of halide minerals.

Fluorite occurs in an extraordinary range of colours:

Purple
Green
Yellow
Blue
Pink
Colourless
Banded combinations

The most valuable stones display strong, pure colours with minimal zoning.

Fluorite has a Mohs hardness of 4, making it relatively soft and suitable primarily for pendants, earrings, and collector’s pieces rather than everyday rings.

It is brittle and can cleave easily along octahedral planes.

Most fluorite is untreated. Rarely, heat treatment may be applied to reduce colour zoning. No coatings or fillings are used in fine-quality stones.

Avoid ultrasonic and steam cleaners.
Do not expose to sudden temperature changes.
Clean with warm water, mild soap, and a soft brush.
Store fluorite separately from harder gemstones to prevent scratches.

Major sources of fluorite include:

China
Mexico
South Africa
Namibia
United States (Illinois, Kentucky)
Spain