A lustrous gray metalloid , it is found in nature mainly as the sulfide mineral stibnite Sb 2 S 3. Antimony compounds have been known since ancient times and were powdered for use as medicine and cosmetics, often known by the Arabic name kohl. The earliest known description of the metal in the West was written in by Vannoccio Biringuccio. For some time, China has been the largest producer of antimony and its compounds, with most production coming from the Xikuangshan Mine in Hunan.
potassium-argon dating - Wiktionary
Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. It was first isolated from potash , the ashes of plants, from which its name derives. In the periodic table , potassium is one of the alkali metals , all of which have a single valence electron in the outer electron shell, that is easily removed to create an ion with a positive charge — a cation , that combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac - colored flame. It is found dissolved in sea water which is 0.
Isotopes of argon
Rubidium is the chemical element with the symbol Rb and atomic number Rubidium is a very soft, silvery-white metal in the alkali metal group. Rubidium metal shares similarities to potassium metal and caesium metal in physical appearance, softness and conductivity. Rubidium is the first alkali metal in the group to have a density higher than water , so it sinks, unlike the metals above it in the group.
Geology can also include the study of the solid features of any terrestrial planet or natural satellite such as Mars or the Moon. Modern geology significantly overlaps all other Earth sciences, including hydrology and the atmospheric sciences , and so is treated as one major aspect of integrated Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface, and the processes that have shaped that structure. It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks. Geology provides the primary evidence for plate tectonics , the evolutionary history of life , and the Earth's past climates.