Basically, there are 2 types of almond. The bitter and sweet types. Bitter almonds are actually the kernel of the apricot which is commonly used in Chinese medicine while the sweet almonds are creamy white, smooth nuts with a brown skin and encased in a shell. In US, almonds are cultivated mainly in California.
When buying whole almonds, always try to buy with their skins on and blanch them yourself for recipes that asked for them as they have more flavor compared to the already-skinned almonds and are also not so dry. Nuts lose their flavor quickly, so only buy them in small quantities as required.
** Asian Online Recipes