Croton tree nuts, horse chestnuts and rosemary peas are some types of inedible nuts. Although these are not edible, manufacturers use them as raw materials in many products, such as fuel, jewelry and medicine.
Croton tree nuts are the seeds of the green to grayish-brown fruits of Croton megalocarpus, a native tree or shrub native to Southeast Asia. Its seeds are inedible but scientists use them in some parts of Asia and South Africa as an economical and alternative source of biofuel. The nuts of the tree have a very high fuel content level. Croton trees grow wild, and fruit development and maturity only takes five months.
Horse chestnuts are inedible and toxic nuts that grow from horse chestnut or conker trees. People oftne mistake the nuts for sweet chestnuts because both nuts are brown in color with light-colored spots. Horse chestnuts, however, do not have tassels or points on the nut, a part that edible chestnuts always have. Although the nuts are inedible, manufacturers sometimes process the seeds to treat certain conditions, such as diarrhea, hemorrhoids, enlarged prostate and swollen veins.
Rosemary pea is also known as Crab's eye, Indian licorice and Love nut. Many people gather the brightly colored cherry fruits as ornaments because of their beautiful seedpods. The seeds or nuts, however, contain Abrin, a toxic protein considered a bio-agent under U.S. law.