Pearl Structure

The prismatic layer within a pearl has a radial structure, individual prismatic crystals of calcite, embedded in the organic matrix, are arranged in such a way that their longitudinal axis points towards the centre of the pearl.

The structure of the nacre layers can be compared with an onion. The individual sheets are studded with aragonite platelets of a polygonal, usually hexagonal shape and are arranged on top of each other that the aragonite platelets come to lie in the familiar brick structure.

In reality, the sheets are made up of segments, as actual growth takes place in stages and may stop after some time before the growth of a new sheet proceeds.

As the individual platelets do not stop growing at the same time, the surface of pearls is not made up of a uniform outer layer. Layers overlap in a terrace-like manner reminiscent of roof tiles.

The pictures below show the details of the pearl structure: