1st: What is Grain Leather?
Grain leather features a pattern on the surface. This pattern comes from the pores and hair follicles particular to the animal which the hides are from.
Grain leather has the surface layer intact and is finished on the grain side.
Now on to defining the types and layers of leather.
Full Grain Leather
Considered to be the highest quality leather, the grain is intact and untreated by buffing, sanding, etc to remove marks, scratches, and other imperfections on the surface of the hide.
Full Grain Leather can develop a rich patina in time that improves the look of the leather.
Top Grain Leather
The 2nd highest quality leather. With the split layer (see graphic) removed, it is thinner and more flexible than Full Grain Leather. The surface is lightly sanded with a finish coat applied. It will not develop a natural patina like Full Grain Leather.
Top Grain Leather also applies to Corrected Grain, which has been lightly sanded to remove scars and defects.
Split leather comes from the corium (the most fibrous part) of the hide. This is revealed once the top grain has been removed.
While splitting, the top grain and bottom split are separated. If the leather is thick enough, it can be split further with a middle and flesh split.
This leather can have an artificial layer applied which could be embossed with leather grain.
Suede leather is made out of split leather.
This term covers many different leathers, mostly those made from splits. Can include suedes, embossed, laminated, and more.
While making leather, dust, trimmings, shavings, etc are created. This is bonded with latex or a similar material and are pressed together. This is often made to look like full or top grain leather. However, it lacks the durability of higher grade leathers.