Gregoryite is an

anhydrous A substance is anhydrous if it contains no water. Many processes in chemistry can be impeded by the presence of water; therefore, it is important that water-free reagents and techniques are used. In practice, however, it is very difficult to achi ...

carbonate mineral Carbonate minerals are those minerals containing the carbonate ion, . Carbonate divisions Anhydrous carbonates *Calcite group: trigonal ** Calcite CaCO3 ** Gaspéite (Ni,Mg,Fe2+)CO3 ** Magnesite MgCO3 **Otavite CdCO3 ** Rhodochrosite MnCO3 ...

that is rich in

potassium Potassium is the chemical element with the symbol K (from Neo-Latin '' kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmos ...

and

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

with the chemical formula . It is one of the two main ingredients of natrocarbonatite, found naturally in the lava of Ol Doinyo Lengai volcano, the other being nyerereite. Because of its anhydrous nature, gregoryite reacts quickly with the environment, causing the dark lava to be converted to white substance within hours. Gregoryite was first described in 1980 and named after the British geologist and author John Walter Gregory (1864–1932), who studied the East African Rift Valley. It occurs associated with nyerereite, alabandite,

halite Halite (), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, p ...

sylvite Sylvite, or sylvine, is potassium chloride (KCl) in natural mineral form. It forms crystals in the isometric system very similar to normal rock salt, halite ( NaCl). The two are, in fact, isomorphous. Sylvite is colorless to white with shades o ...

, fluorite and calcite.

References

{{Reflist Calc-alkaline rocks Hexagonal minerals Minerals in space group 186 Carbonate minerals Volcanology