2. Basic components

Cells and cell residues. Fragment of less than 5 or 10 connected cells.

Amorphous organic fine material. It can be two types:

Monomorphic. Uniform material without any residues of coarse fragments being observed (<5%).

Polymorphic. Residues of coarse fragments can be distinguished (>5%).

Punctuations. Very small dark points (approximately 1 mm).

Organic pigment. The mineral material is stained by the organic material.

There is a description of: size, shape, colour, transparency, birefringence, degree of alteration, etc.