Colombian pseudo-tektites are such clean that they are even suitable for faceting! About Colombianite Colombianite pseudo-tektites are found in the departments of Antioquia and Caldas in Colombia. Formation The type of rock that constitutes a Colombianite pseudo-tektite is called quartz porphyry. This type of rock is made up of large crystals of quartz embedded in a smaller quantity of feldspar. The quartz crystals give the rock a glassy appearance, and the overall composition is similar to that of granite. /Every piece comes from my own collection./ International shipping via registered priority mail or other courier service with track & trace.