Example of an idiomorph quartz crystal (left) and the 3d-reconstruction after tomography (right).
Inclusions in the quartz crystall can be separated due to their differences in density, here shown are air-inclusions (blue) and mineral-inclusions (red).

The filling of cracks in gemstones with lead glass by thermal treatment is used to enhance the clarity of the objects and thus rise market prices. µ-CT is a fast and efficient tool to identify this kind of treatment.

Radiograph of a clarity enhanced rubin (upper left). Inclusions and impurities, as well as lead glass filled cracks are clearly visible in the transparent image.

After segmentation of the 3d-data the surface is shown by volume rendering (upper right). Further segmentation allows the illustration of the lead glass filled cracks, combined with the slightly transparent ruby surface (lower left), or simply the filled cracks (lower right).