One of the world's most ancient spices, green cardamom comes from the seeds of a ginger-like plant and is native to southern India. The ancient Egyptians chewed cardamom seeds as a tooth cleaner; the Greeks and Romans used it as a perfume. Vikings came upon cardamom about one thousand years ago, in Constantinople [modern Istanbul], and introduced it into Scandinavia, where it remains popular to this day. Green cardamom is one of the most expensive spices by weight, but little is needed to impart the flavor.
Specific uses of green cardamom vary with different cuisines and cultures. Cardamom is a key ingredient in sweet baked goods in Scandanavia, like holiday Julekake and Finnish pulla. In the Arab world, ground green cardamom is used in strong brewed coffee and in rice pilaf. In India, green cardamom features prominently in all kinds of curries, spice mixes, sweet treats and Masala chai spiced tea. Amusingly, green cardamom is also an ingredient in Wrigley's Eclipse Breeze Exotic Mint chewing gum.
Green cardamom is a welcome addition to chicken, duck, red meats, lentils, curries, oranges, peas, rice and squash. Cardamom is also delicious in mulled wine and spiced punch drinks, in pickles [esp picked herring], and with shellfish.
About black cardamom: Whereas green cardamom is used in savory and sweet dishes. black cardamom is used almost exclusively in savory cooking [and in traditional tea, chai]. Black cardamom is considered a warm spice, while green cardamom is more of a cooling spice. Black cardamom is much larger and stronger than its cousin green cardamom.