Feldspar (including electrical insulators, sanitaryware, pottery, tableware, and tile) and other uses, such as fillers, accounted for the remainder. In earth sciences and archaeology, feldspars are used for K-Ar dating, argon-argon dating, and luminescence dating. In October 2012, the Mars Curiosity rover analyzed a rock that turned out to have a high feldspar content. Feldspar Feldspars (KAlSiO – NaAlSiO – CaAlSiO) are a group of rock-forming tectosilicate minerals that make up about 41% of the Earth's continental crust by weight. Feldspars crystallize from magma as veins in both intrusive and extrusive igneous rocks and are also present in many types of
Tales from the Flat Earth of agate, the second is made of blue steel, and the third gate is made of black fire. There is only one city in the Underearth – Druhim Vanashta, the city of demons. It is made of precious minerals, gems, and metals and is beautiful, though its inhabitants are cruel and wicked. The Flat Earth appears to include temperate, sub-tropical, and tropical zones, including many deserts. Since "polar" regions would be impossible on a flat world, they are not mentioned in the series. There are many seas, but bodies of water large enough to be called "oceans" do not appear