Fluorite is a beautiful mineral that occurs in a wide variety of colours. The stone known as "rainbow fluorite" exhibits zones of colour within the same crystal.
The different colours are caused by impurities. In its purest form fluorite is colourless and transparent.
Crystals are generally well formed but fluorite also crystallises in masses. In this habit crystals grow tightly together to form a large shapeless mass.
Fluorite is soft and fragile so must be handled carefully. Internal fractures and minor surface anomalies are not uncommon.
Material from China is often heated which lightens and enhances the colour. Names such as "Candy" or "Watermelon" fluorite tends to be used for this material.