native shale backing (0.5mm), quartz cap (1.0mm)
15.6mm x 8.1mm
Ammolite is a very fragile and soft stone prone to flaking and scratches. As it is also very brittle, it is atached to a backing material, or left attached to its native shale (Quality Ammolite backing should not exceed 1.5mm thichness). The front is then filled over with an epoxy, or capped by synthetic spinel, corundum, or quartz.
Even "solid" pieces are protected by an epoxy coating.