Geographic Minerals

For many years, the ‘sailing stones’ of Death Valley represented one of the most curious mysteries that scientists had never been able to solve…until recently,…

“Cave of the Crystals” or “Giant Crystal Cave” (Spanish: Cueva de los Cristales) are the largest natural crystals known, and it has located hundreds of…

Magadiite is a hydrous sodium silicate mineral [NaSi7O13(OH)3·4(H2O)] which precipitates from alkali brines as an evaporite phase. It is a soft white hydrous sodium silicate…

Madocite is a mineral with a general formula of Pb17(Sb, As)16S41. It is an orthorhombic-pyramidal grayish black mineral containing antimony, arsenic, lead, and sulfur. It…

Mackinawite is an iron-nickel sulfide mineral with formula (Fe, Ni)1+xS (where x = 0 to 0.11). It is a tetragonal iron-nickel sulfide mineral that occurs…

Macdonaldite is a rare barium silicate mineral with a chemical formula of BaCa4Si16O36(OH)2·10H2O. It is an orthorhombic-dipyramidal mineral containing barium, calcium, hydrogen, oxygen, and silicon.…

Macaulayite is a red, earthy, monoclinic mineral, with the chemical formula (Fe3+, Al)24Si4O43(OH)2. It is monoclinic blood-red mineral containing aluminum, hydrogen, iron, oxygen, and silicon.…

A lodestone is a naturally magnetized piece of the mineral magnetite. It is a piece of magnetite that has magnetic properties and attracts iron or…

Limonite is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. It is a native hydrous ferric oxide of variable…

Lignite, often referred to as brown coal, is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It is a sedimentary rock that…

Lechatelierite is silica glass, amorphous SiO2, non-crystalline mineraloid. This mineral is an amorphous form of silica formed by the fusion by the heat of silica…

Larimar also called “Stefilia’s Stone”, is a rare blue variety of the silicate mineral pectolite found only in the Dominican Republic, in the Caribbean. Its…