Louisfuchsite
Chemical formula: Ca₂(Mg₄Ti⁴⁺₂)(Al₄Si₂)O₂₀
Louisfuchsite is an extremely rare mineral from the sapphirine group, discovered in a meteorite, distinguished by its unique chemical composition with titanium.
Properties
- Mohs hardness
- 5.5-6
- Luster
- Vitreous
- Density
- 3.44
- Transparency
- Transparent
- Crystal system
- Triclinic
Diagnostic features
## Identification Identification of louisfuchsite is impossible without advanced laboratory techniques. It requires chemical analysis (electron microprobe - EDS/WDS) and structural studies (X-ray diffraction - XRD or electron diffraction). Under a microscope (in transmitted light), it is transparent and light brown. ## Distinguishing from Similar Minerals This mineral occurs in association with other minerals from the sapphirine group, as well as with grossite, spinel, and perovskite. Distinguishing it from these minerals based on visual characteristics is impossible. The key is to determine its unique chemical composition, particularly its high titanium content, which differentiates it from sapphirine sensu stricto. ## Crystal Forms Louisfuchsite forms only very fine, anhedral grains within other minerals. No euhedral, well-formed crystals have been observed.
Geological environment
## Genesis Louisfuchsite formed in the unique environment of melting rock within the parent body of the asteroid from which the NWA 4964 meteorite originated. It formed as a result of reactions between calcium- and aluminum-rich minerals (so-called CAIs - Calcium-Aluminum-rich Inclusions) and the surrounding silicate melt under high-temperature conditions. ## Mineral Associations This mineral occurs in close association with other rare meteoritic minerals. Its immediate surroundings include grossite, spinel, perovskite, and other unidentified phases from the sapphirine group. ## Localities The only confirmed locality of louisfuchsite in the world is the NWA 4964 meteorite, found in the Northwest African region. This is the so-called type locality (place of first discovery).
Rarity
Extremely rare
For collectors
## Quality Criteria The quality of a specimen in the case of louisfuchsite is defined solely by its scientific value. Since the mineral is microscopic and embedded in rock, it is not evaluated for color, clarity, or form in the traditional sense. The most valuable are meteorite fragments in which the presence of louisfuchsite has been analytically confirmed, and the grains are as "large" as possible (on the micrometer scale) and well-isolated within the matrix. ## Popular Localities The only source of louisfuchsite is the NWA 4964 meteorite. Fragments of this meteorite in which this mineral has been identified are primarily found in the collections of scientific and university institutions, such as the University of Hawaii. Availability on the collector's market is practically zero.
Care and storage
## Cleaning Due to the microscopic size of the grains and their occurrence exclusively within the meteorite's rock matrix, cleaning individual specimens is impossible and impractical. Any attempts to clean a meteorite fragment should be limited to very careful dust removal using a soft brush or compressed air from a safe distance. ## What to Avoid Avoid contact with any chemicals, acids, or ultrasonic cleaners, which could damage not only the mineral itself but also the entire delicate structure of the meteorite. Protect the specimen from extreme temperature changes and humidity. ## Storage Meteorite fragments containing louisfuchsite should be stored under stable conditions, preferably in a padded "membrane box" or a specialized display case, away from direct sunlight, dust, and humidity. Stable temperature and low humidity are crucial for preserving the specimen in an intact state.