Tektite, TEHK tyt, is a rounded, glassy stone that may resemble a ball, disk, rod, button, dumbbell, or teardrop. Tektites have smooth, grooved, or pitted surfaces and range in color from jet-black to greenish or yellowish. Most tektites are peanut-sized and weigh about 0.1 ounce (3 grams). The largest known tektite weighs about 28 pounds (13 kilograms). The youngest tektites known, which formed about 750,000 years ago, are found scattered across Australia and Southeast Asia. Other major tektite fields occur in the southern and eastern United States and Cuba; the Czech Republic, Slovakia, and Austria; Cote d'Ivoire; and Libya.