Löweite

Chemical formula: Na₁₂Mg₇(S⁶⁺O₄)₁₃(H₂O)₁₅

Löweite is a rare, water-soluble sodium and magnesium sulfate, forming colorless or yellowish, vitreous crystals.

## Characteristics Löweite is a hydrated sodium and magnesium sulfate, belonging to the evaporite mineral group. It occurs as well-formed, dipyramidal or tabular crystals, which can reach considerable sizes. It often also forms granular aggregates. It is a brittle mineral with a vitreous luster. Due to its water solubility, specimens must be protected from moisture. ## Physical Properties This mineral is characterized by a low hardness of 2.5-3 on the Mohs scale, meaning it can be scratched with a copper wire. Its density is approximately 2.37 g/cm³. It has a vitreous luster and is transparent. The fracture is conchoidal. ## Colors and Varieties Löweite is most often colorless, but can take on yellowish, reddish-orange, or orange hues, likely due to the presence of microscopic inclusions of other minerals, e.g., hematite. It is colorless in transmitted light. ## History and Name The mineral was named in 1846 by the Austrian mineralogist Wilhelm Haidinger in honor of Alexander von Löwe, an Austrian chemist who first performed a chemical analysis of this substance. The type locality, from which the first described specimens originated, is the rock salt deposit in Bad Ischl, Austria. ## Uses Löweite has no significant industrial use. However, it is a valued and sought-after collector's mineral due to its rarity, attractive crystal forms, and specific origin.

Properties

Mohs hardness: 2.5-3
Luster: Vitreous
Streak: White
Density: 2.374
Fracture: Conchoidal
Transparency: Transparent
Crystal system: Trigonal

Diagnostic features

## Identification A key diagnostic feature of löweite is its water solubility. It is also distinguished by characteristic, dipyramidal crystals with a vitreous luster, low hardness, and occurrence in paragenesis with other salts (evaporites). ## Distinguishing from Similar Minerals It can be confused with other colorless or yellowish salt minerals, such as halite, sylvite, or blödite. It is distinguished from halite and sylvite by its trigonal crystal form (halite and sylvite crystallize in the isometric system, forming cubes). From blödite, with which it often co-occurs, it is distinguished by its crystallographic form and slightly different physical properties. The water solubility test is helpful but not unique to this mineral. ## Crystal Forms Löweite crystals most often take the form of trigonal dipyramids, often flattened, resembling rhombohedra. It also occurs as granular aggregates and compact masses embedded in rock salt.

Geological environment

## Genesis Löweite is an evaporite mineral. It forms by precipitation from saline lake or sea waters in a dry and hot climate. It crystallizes in the late stage of evaporation, when the solution reaches a high concentration of magnesium and sodium sulfates. ## Mineral Associations It most often co-occurs with other salt minerals, such as halite, anhydrite, polyhalite, blödite, vanthoffite, kainite, sylvite, and gypsum. ## Localities The most important löweite occurrences are associated with potash-magnesium salt deposits. Classic localities include deposits in Austria (Bad Ischl - type locality, Hallstatt), Germany (e.g., in salt mines in Lower Saxony and Saxony-Anhalt), as well as in the USA (New Mexico, Texas) and Kazakhstan.

Rarity

Rare

For collectors

## Quality Criteria Large, well-formed, transparent, and freestanding löweite crystals are most valued by collectors. Intense orange or reddish coloration, caused by hematite inclusions, adds to its attractiveness. Specimens on a matrix of halite or other salt minerals are also highly prized. ## Popular Localities Classic, historical specimens come from Austrian salt deposits near Salzburg (Bad Ischl, Hall). Currently, specimens from German salt mines also appear on the collector's market.

Care and storage

## Cleaning Löweite specimens must not be cleaned with water or any liquids, as the mineral is soluble in them. Only a soft brush or compressed air from a safe distance should be used to remove dust. ## What to Avoid Contact with water, water vapor, and high humidity must be strictly avoided, as these can cause the specimen to dissolve and be destroyed. The mineral should be protected from chemicals and sudden temperature changes. ## Storage Löweite requires storage in dry conditions. It is best to place it in a sealed, closable display box (a "membrane box") or in a display cabinet with a desiccant (e.g., silica gel).