Agate slice from Brazil on brass base

This slice of Brazilian agate is a perfect illustration of the geological phenomena that gave rise to it. It comes from volcanic cavities formed by gas bubbles trapped in basaltic lava, and bears witness to a long process in which successive infiltrations of silica deposited layer after layer of various oxides such as haematite and limonite, responsible for its characteristic hues.
The deep brown outline contrasts with the golden, brown and white hues that spread out in concentric circles. This visual effect is the result of successive deposits, creating a harmonious alternation of colours. A small crystallised cavity adds an extra mineral touch, while the rest of the piece reveals the purity of the agate.
Mounted on a brass base, this slice reveals all its finesse when the light shines through it (picture 2 and 3), highlighting the subtle transparency and detail of the different layers.