Halides

Halides

Sylvite is an evaporite mineral which can be distinguished from halite by its bitter taste. It has the same origin, mode of occurrence, and associations as halite, but is much rarer. It was named after Francois Sylvius de le Boe (1614-1672), a physician and chemist of Leyden, Netherlands.

Natural salt. It occurs as evaporite deposits in saline lakes, bedded sedimentary deposits, or salt domes. It is characterized by its cubic habit and salty taste and comes from the Greek word meaning "salt".

Fluorite is a common and widely-distributed fluorescent mineral that was discovered in 1529. The name comes from the Latin flure meaning "to flow". It is found as a common gangue mineral in hydrothermal veins, especially those of lead and silver, and is associated with hot springs deposits. It is used as a flux in steel-making and as a source of fluorine.

An interesting feature of this mineral is that it "disappears" when immersed in water due to the similarity in refractive indices. It is named from two Greek words meaning "frost" and "stone", in allusion to its frosty appearance. Historically, it was used as an aluminum ore, and when bauxite became the ore of aluminum, cryolite was used as a flux in the electrolytic process.

First discovered in 1856, this mineral was named after Rudolf von Carnall (1804-1874), a Prussian mining engineer. It is found in saline marine deposits by action of high potash fluids such as deposits in Stassfurt, Germany and eastern New Mexico. It is a source of potassium and magnesium.

Named after the type locality, in the Atacama Desert of northern Chile, this mineral is a secondary copper mineral formed through the oxidation of other copper minerals, especially in arid, saline conditions.

The minerals that make up the halide class include those in which the halogen elements of chlorine, bromine, fluorine, and iodine are combined with one or more metals.

Minerals of the halide class all:

  • have relatively low hardness.
  • can be transparent.
  • have low specific gravities.
  • have good cleavage.
  • are poor conductors of heat and electricity.