All the secrets of minerals are far from having been revealed… Many scientific studies focus on increasing understanding of how Nature managed to create such exceptional structures, the aim being to exploit their tremendous properties to help synthesize new structures with promising application potential.

These images taken at the ILM show minerals and crystals such as topazes and opals bathed in multiple sparkling colours which present them a most unusual way. To "clothe" them in red, blue or green, the scientists play on the interactions between light and matter. The matter is excited by different light sources (white, infrared, ultraviolet light, lasers, etc.) and subsequently a residual colouring or luminescence can be observed. However the phenomena are not produced for artistic reasons. They above all enable researchers to obtain precious information about the structure, composition and physicochemical properties of mineral materials… without damaging them in any way.

The effects of the optics on these images derive from two phenomena. Firstly the diffraction of light on the materials gives them the various different shades of colours which can be observed. This can be qualified as a physical colour phenomenon. Secondly the emission of light by these materials is the result of the phenomenon of photoluminescence. The latter is a combination of two other more familiar phenomena - fluorescence which is notably used in safety vests and phosphorescence which makes objects such as those found in children's bedrooms glow in the dark.

Thanks to Gérard Panczer for his contribution.