Fluorescent minerals

Sometimes if you shine a high energy beam of light, such as an ultraviolet (UV) torch, on an object it will glow a different colour.

Many types of mineral fluoresce under UV light.

Fluorite was the first mineral known to fluoresce. The word fluorescence comes from the original name of this mineral, ‘fluorospar’. In its purest form viewed in daylight, fluorite is colourless. Impurities such as iron can cause fluorite to appear red, orange, or yellow. Copper can turn it blue or green.

Calcite is a very common calcium carbonate mineral. It is found around the world and fluoresces a variety of different colours including pink, orange, red, yellow and violet depending on where it has come from and the impurities it contains.

Visual description: three lumps of minerals. Each is formed of irregular grey rock, one with yellow patches. Their surfaces are densely coated in clusters of crystals. One mineral has clear crystals, another purple and the third blue. When under ultraviolet light, the crystals glow brightly.