A
modified form of
cellulose found in the
endosperm tissue of
seeds. The cell walls of the endosperm
tissue become thickened with hemicellulose until they
occlude most of the
lumen (i.e. they cells become completely filled with
hemicellulose). These thick-walled endosperm cells become very
hard when
dry, with hard, bony texture similar to ivory. The large seeds of several palm tree
species are rich in
hemicellulose, and this is the source of
vegetable ivory.
Like wood, vegetable ivory is essentially composed of thick-walled dead cells; however, unlike
grainy hardwoods it has a texture and hardness similar to
ivory. Vegetable ivory is remarkably dense, with a rating of about 2.5 on the
scale of
mineral hardness. (3.5 for a copper penny and 10 for diamond). Ivory-nuts can be polished in a
stone tumbler, as you would polish
agates and
quartz: by using
tin oxide and a
buffing wheel.