The almond that we think of as a nut is technically the seed of the fruit of the almond tree, a glorious medium-size tree that bears fragrant pink and white flowers. Like its cousins, the peach, cherry and apricot trees, the almond tree bears fruits with stone-like seeds (or pits) within. The seed of the almond fruit is what we refer to as the almond nut. Almonds are off-white in color, covered by a thin brownish skin, and encased in a hard shell. Almonds are classified into two categories: sweet (Prunus amygdalu var. dulcis) and bitter (Prunus amygdalu var. amara). Sweet almonds are the type that are eaten. They are oval in shape, usually malleable in texture and wonderfully buttery in taste. They are available in the market either still in their shell or with their shell removed. Shelled almonds are available whole, sliced or slivered in either their natural form, with their skin, or blanched, with their skin removed. Bitter almonds are used to make almond oil that is used as a flavoring agent for foods and liqueurs such as Amaretto. They are otherwise inedible as they naturally contain toxic substances such as hydrocyanic acid. These compounds are removed in the manufacturing of almond oil.