Tektite is not really a gemstone--it's a form of natural glass (much like obsidian) caused by heat. Rather than the heat being from volcanos, however, the heat that makes tektite comes from atmospheric friction. Meteorites enter the planet's atmosphere and are pulled down by gravity--the friction caused by moving through...
Some legends say that green tektites are emeralds from heaven. Their scarcity makes them valuable; in Europe during the middle ages, tektite was used as a good luck talisman, in jewelry and for trade.
Tektites, due to being a product of extraterrestrial phenomena, are associated with worlds outside our own. They are believed to facilitate communication with otherworldly realms and encourage spiritual growth. In some traditional societies, tektites are worn to promote fertility for both men and women.
$5 pieces are approximately 1.5"-2"