Branchite

Chemical formula: C<sub>₂₀</sub>H<sub>₃₄</sub>

Branchite (hartite) is a very rare organic mineral from the group of fossil resins, being a natural, crystalline hydrocarbon.

## Characteristics Branchite, considered a synonym of hartite, is an organic mineral belonging to the hydrocarbon group. It occurs in the form of small, tabular or bladed crystals, forming aggregates, coatings, and crystalline masses. In appearance, it resembles paraffin or wax. It is very soft, light, and brittle, and feels greasy to the touch. It is usually colorless, white, or yellowish. ## Physical Properties This mineral is characterized by exceptionally low hardness, only 1 on the Mohs scale, which means it can be scratched with a fingernail. Its density is also very low, close to that of water, making specimens seem extremely light. It has a resinous, waxy, or greasy luster. It is transparent to translucent. It is flammable and melts at a low temperature. ## Colors and Varieties Branchite is most often colorless, white, grayish-white, or yellowish. No color varieties are distinguished. The name branchite is a historical synonym for hartite, which is officially recognized by the International Mineralogical Association (IMA). ## History and Name The name branchite was given in 1858 by Charles Upham Shepard and comes from its discovery location – the lignite mine in Monteviale (Brancha) in the province of Vicenza, Italy. This mineral is currently classified as hartite, named after the Austrian geologist Karl von Hartt. ## Uses Due to its extreme rarity and small size, branchite (hartite) has no industrial application. It is solely an object of scientific and collecting interest.

Properties

Mohs hardness: 1
Luster: Resinous to waxy
Streak: White
Density: 1.05-1.07
Cleavage: Perfect on {010}
Fracture: Conchoidal
Transparency: Transparent to translucent
Crystal system: Triclinic

Diagnostic features

## Identification Key diagnostic features include extreme softness (hardness 1 on the Mohs scale), very low density (the specimen is light like plastic), greasy or waxy appearance and feel, and flammability. Its occurrence environment – brown coal (lignite) deposits – is also characteristic. ## Distinguishing from Similar Minerals It can be confused with other fossil resins, such as amber or copal, which are, however, much harder (hardness 2-2.5). From soft inorganic minerals, like talc, it is distinguished by lower density, resinous luster (talc has a pearly luster), and flammability. Paraffin wax has a similar appearance but is an artificial product. ## Crystal Forms It forms small, tabular or bladed crystals, often arranged in radial aggregates. It also occurs in the form of granular aggregates, coatings, and thin veins intergrown with the host rock (lignite).

Geological environment

## Genesis Branchite (hartite) is a mineral of organic origin. It forms as a result of diagenetic processes (fossilization) of conifer resins in anaerobic conditions, within brown coal (lignite) deposits. ## Mineral Associations It most often co-occurs with brown coal (lignite). Other organic minerals (e.g., other fossil resins) and secondary minerals forming under the same conditions, such as gypsum, calcite, or sulfur, may accompany it. ## Localities The most important localities worldwide are historical sites in Europe. The type locality for branchite is Monteviale in Italy. For hartite, of which branchite is a synonym, the type locality is Oberhart in Carinthia, Austria. This mineral has also been found in Idrija in Slovenia and Valchov in the Czech Republic.

Rarity

Very rare

For collectors

## Quality Criteria The most valued by collectors are specimens with well-formed, sharp crystals, which is a great rarity. The size of the crystals and their abundance on the rock matrix (lignite) are also important. Clean specimens, free of impurities and with a distinct, white or yellowish color, are more highly rated. Samples from classic, historical localities have high value. ## Popular Localities Specimens from historical localities in Austria (Oberhart) and Italy (Monteviale), which yielded the best-formed crystals, are considered the best. Finds from other localities are much rarer on the collector's market.

Care and storage

## Cleaning It should only be cleaned dry, using a very soft brush to remove dust. Contact with water, especially hot water or detergents, is unacceptable and can damage the specimen. ## What to Avoid The mineral is extremely sensitive to heat – it melts at around 75°C, so it should be kept away from heat sources, lamps, and direct sunlight. It is flammable. All organic solvents, acids, and bases should be avoided. As a very soft and brittle mineral, it is susceptible to scratches and mechanical damage. ## Storage Branchite specimens are best stored in closed, padded boxes (e.g., "micromount" type), which protect against dust, light, and physical damage. It should be isolated from other minerals to avoid scratches.

Sources

IMA Mineral List (CNMNC)