Star fruit or carambola come from the small Southeast Asian tree Aver-rhoa carambola, a member of the wood sorrel (Oxalis) family. These medium-sized, yellowish fruits are notable for their starlike cross section, a decorative touch in salads and garnishes, for an aroma with notes of Concord grapes and quince, and for the presence of oxalic acid, mainly in the five ridges. When unripe and especially rich in oxalic acid, star fruit are sourly reminiscent of similarly endowed sorrel and are used to clean and polish metal! Star fruit are colored by carotenoid pigments, including beta-carotene. A relative, the bilimbi, is too tart to eat fresh and in the tropics is made into preserves and drinks.