Trattnerite
Chemical formula: Fe<sup>3+</sup><sub>2</sub>(Mg<sub>3</sub>Si<sub>12</sub>)O<sub>30</sub>
Trattnerite is an extremely rare iron and magnesium silicate, forming black, acicular crystals in volcanic vugs.
Description
## Characteristics Trattnerite is a complex iron and magnesium silicate belonging to the osumilite group. It forms very small, acicular crystals up to 1 mm long and only a few micrometers in diameter. These crystals most often occur as radial or tangled aggregates. The mineral is opaque and black in color. ## Physical properties The luster of trattnerite is vitreous. Due to the small size of the crystals, the hardness has not been determined. The density calculated from the chemical composition and unit cell parameters is 3.03 g/cm³. The streak is gray. ## Colors and varieties The mineral occurs exclusively in black. No colored or commercial varieties are known. ## History and name Trattnerite was officially recognized as a new mineral by the International Mineralogical Association (IMA) in 2019 (IMA2019-039). Its name honors Franz Trattner (born 1963), an Austrian collector and amateur mineralogist who found the first specimens of this mineral and submitted them for scientific research. ## Applications Due to its extreme rarity and microscopic size, trattnerite has no practical application. It is solely an object of scientific and collecting interest.
Diagnostic features
## Identification Amateur identification of trattnerite is practically impossible. Indicative features may include black color, vitreous luster, and the form of radial aggregates composed of very thin needles. A key clue is its occurrence in gas vesicles in andesite in association with tridymite. Definitive identification requires advanced analytical techniques such as X-ray diffraction (XRD) and chemical microanalysis (EDS). ## Distinguishing from similar minerals Trattnerite can be visually confused with other black, acicular minerals, such as aegirine, some tourmalines (schorl), or amphiboles. The primary distinguishing feature is its unique environment of occurrence – vugs in andesite at the only known locality. Without knowing the origin of the specimen, distinguishing it from more common minerals is impossible without specialized equipment. ## Crystal forms Trattnerite crystallizes in the form of very thin, elongated, acicular crystals. These crystals form characteristic, radially diverging aggregates, as well as tangled, felt-like clusters.
Geological environment
## Genesis Trattnerite is a mineral of volcanic origin. It forms in the late stage of magma crystallization, in gas vesicles (vugs) within andesitic lavas. Its presence is associated with high-temperature processes occurring in cooling volcanic rock. ## Mineral associations The mineral directly associated with trattnerite at its locality is tridymite (a high-temperature polymorphic variety of quartz). ## Localities Only one locality of trattnerite is known worldwide. This is its type locality, located in the Kožuf volcanic massif, near the village of Konjsko in North Macedonia.
Rarity
Extremely rare
Collector aspects
## Quality criteria The quality of trattnerite specimens, being a "micromount" type mineral, is assessed based on several criteria. The most important is the abundance and development of aggregates – the denser and more defined the radial clusters, the more valuable the specimen. Specimens where trattnerite contrasts with a light background of the host rock or co-occurs with well-formed tridymite crystals are also highly valued. Due to its fragility, the absence of damage to the delicate needles is crucial. ## Popular localities The only source of trattnerite specimens on the collector's market is its type locality in the Kožuf mountains in North Macedonia. All available specimens come from this single location.
Care and storage
## Cleaning Trattnerite specimens are extremely delicate and susceptible to mechanical damage. Cleaning should be kept to an absolute minimum. Only very careful dust removal using a stream of compressed air from a safe distance is permissible. Contact with water and any chemical agents should be avoided. ## What to avoid Ultrasonic cleaners, which would destroy the fragile aggregates, must be absolutely avoided. The mineral should be protected from contact with acids and other chemicals, as well as from sudden temperature changes and direct impact. The acicular crystals are very brittle. ## Storage The best way to store specimens is to place them in a sealed "micromount" box, which protects against dust, moisture, and shocks. Display should be away from sources of vibration.