Fluorite

Fluorite (calcium fluoride) is one of the most colourful minerals in the world — it occurs in purple, green, blue, yellow, pink, colourless, and multicoloured combinations that can shift dramatically within a single specimen. Its name gives us the word 'fluorescence' — fluorite was one of the first minerals discovered to glow under ultraviolet light, a property so distinctive that the effect was named after the stone. China is the world's largest producer, with major deposits also in Mexico and South Africa. Purple and green fluorite are particularly prized.

The ancient Romans called fluorite murrhine and used it for the most expensive drinking vessels ever made — Pliny records that one Roman paid a million sesterces for a single fluorite cup. Its value was not the material itself (fluorite is relatively soft and common) but the extraordinary colour and banding patterns that no artisan could replicate. The Emperor Nero reportedly wept when he broke his fluorite cup in a rage, the loss being irreplaceable.

In contemporary crystal work, fluorite is called the 'genius stone' for its association with mental clarity, concentration, and the absorption of new information. It is the crystal of study, analysis, and organised thinking — bringing order to complex systems, clearing mental fog, and allowing the holder to hold multiple pieces of information simultaneously without losing the thread. It is also one of the most effective stones for cleaning and stabilising the aura, making it valuable for those who work in energetically demanding environments.