Buying Tips: Mangosteens that are sold in stores or markets in North America are generally ripe; the only problem may be over-ripeness. Mangosteen has a kind of hard 'shell' which should be intact. If the outside is indented or soft, don't buy it. Also look for more or less even skin tone - not too many brown blotches. Some green or red in the stem or leaves is also a good sign. If leaves and/or stem are completely brown and fruit is blotchy or indented, the mangosteen is over-ripe.