Geographic Minerals

“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…

Lapis lazuli or lapis for short is a deep-blue metamorphic rock used as a semi-precious stone that has been prized since antiquity for its intense…