Alfredcasparite

Chemical formula: Sr₂Ti₄+O(Si₂O₇)

A very rare strontium and titanium silicate, forming microscopic, prismatic crystals, known from only one locality in the world.

## Characteristics Alfredcasparyite is a very rare mineral from the sorosilicate group, with a complex chemical composition containing strontium and titanium. It occurs as very small, well-formed crystals, rarely exceeding half a millimeter in size. Typical specimens form prismatic or tabular crystals, often grouped into radial or fan-shaped aggregates. Due to its microscopic size, it is classified as a micromount mineral. ## Physical Properties Alfredcasparyite crystals are characterized by a vitreous luster and are transparent to translucent. The calculated density for this mineral is 4.31 g/cm³. Its Mohs hardness has not yet been determined. ## Colors and Varieties This mineral is most often pale brownish-yellow, and can also be colorless. No color or commercial varieties have been distinguished. ## History and Name Alfredcasparyite was officially recognized as a new mineral by the International Mineralogical Association (IMA) in 2015. Its name honors Alfred Caspar (born 1952), a German mineral collector who found the first samples of this mineral in the Caspar quarry in Germany. This discovery is an example of the contribution of hobbyist collectors to science. ## Applications Due to its extreme rarity and microscopic size, alfredcasparyite has no industrial applications. It is solely an object of scientific interest and a prized acquisition for advanced systematic and regional collections.

Properties

Luster: Vitreous
Streak: White
Density: 4.31
Cleavage: Good on {100}
Transparency: Transparent to translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Identification of alfredcasparyite is impossible without advanced analytical equipment. Key indicators include: microscopic size, specific locality (Caspar quarry in Eifel), characteristic geological environment (volcanic ejecta), and co-occurrence with other rare minerals. Final confirmation requires chemical analysis (e.g., by EDS method). ## Distinguishing from Similar Minerals It can be confused with other fine-grained, light-colored silicates found in the same environment, such as some zeolites or other rare calcium and strontium minerals. Definitive differentiation is only possible based on chemical and crystallographic analysis. ## Crystal Forms It forms elongated, prismatic or flattened, tabular crystals. It often occurs as small, radial or fan-shaped aggregates, embedded in cavities of the host rock.

Geological environment

## Genesis Alfredcasparyite forms under conditions of contact metamorphism at very high temperatures. It crystallizes within calcareous-silicate rock fragments (ejecta) that were ejected during a volcanic eruption. ## Mineral Associations This mineral co-occurs with a rich assemblage of minerals typical of the Bellerberg volcano, such as calcite, diopside, forsterite, magnesioferrite, sharyginite, cuspidine, as well as other rare silicates and oxides. ## Localities The only confirmed locality of alfredcasparyite in the world is its type locality – the Caspar quarry, located at the foot of the Bellerberg volcano in the Eifel region, in the state of Rhineland-Palatinate, Germany.

Rarity

Extremely rare

For collectors

## Quality Criteria As a micromount mineral, alfredcasparyite is evaluated according to specific criteria. Specimens with sharply terminated, well-formed, and undamaged crystals are most highly valued. Their abundance on the rock matrix, attractive arrangement (e.g., in the form of aesthetic aggregates), and the presence of rare associated minerals are also important. ## Popular Localities The only source of collectible specimens is the type locality – the Caspar quarry in Germany. Material from this location is highly sought after by specialists in rare minerals and collectors of minerals from the Eifel region.

Care and storage

## Cleaning Alfredcasparyite specimens are extremely small and fragile, so cleaning is highly inadvisable. Any attempts at mechanical or chemical cleaning can irreversibly damage the crystals. If dust removal is necessary, a gentle stream of air from a photographic blower bulb can be used. ## What to Avoid Contact with any chemicals, ultrasonic cleaners, and water should be strictly avoided. The mineral is sensitive to shocks and impacts, which can cause it to chip from the host rock. ## Storage Specimens should be stored exclusively in specialized, sealed micromount boxes, which protect them from dust, moisture, and mechanical damage. Exposure to direct sunlight and sudden temperature changes should be avoided.

Sources

IMA Mineral List (CNMNC)