The Encyclopedia · Stones & materials
Agate
A banded chalcedony, found in layers of colour; the layers make it ideal for cameos.
Layered agates such as sardonyx and onyx have been carved into cameos since antiquity, using the light layer for the figure and the dark layer for the ground. Agate has also been dyed since the nineteenth century to give it stronger colours.
What to look for
On cameos and carved pieces, look for cracks running through the layers and for chips on raised details.
In the collection
Agate, available now
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