Kenotobermorite

Chemical formula: Ca<sub>4</sub>Si<sub>6</sub>O<sub>15</sub>(OH)<sub>2</sub>·5H<sub>2</sub>O

Kenotobermorite is a rare calcium silicate forming small, bladed crystals with a pearly luster, found in altered limestones.

## Characteristics Kenotobermorite is a hydrated calcium silicate belonging to the tobermorite group. It forms very small, thin crystals with a bladed or fibrous habit, often arranged in rosette-like or spherulitic aggregates. Individual crystals rarely exceed 1 mm in length. The mineral is usually white or colorless, with a characteristic pearly luster on cleavage surfaces. ## Physical Properties Kenotobermorite has a hardness of approximately 4.5 on the Mohs scale. Its density is about 2.43 g/cm³. It exhibits perfect cleavage in one direction, which, combined with the small size of the crystals, makes it brittle. The luster is pearly on cleavage planes and vitreous on other surfaces. ## Colors and Varieties This mineral is typically colorless or white. No colored or commercial varieties have been distinguished. ## History and Name The name "kenotobermorite" comes from the Greek word *kenos* meaning "empty" or "lacking" and refers to the mineral tobermorite. The prefix "keno-" indicates a vacancy (empty site) in one of the structural positions compared to other minerals in this group. It was formally described as a new mineral species by the IMA in 2014. ## Applications Kenotobermorite has no industrial significance. It is solely an object of scientific and collector interest due to its rarity and specific structure.

Properties

Mohs hardness
4.5
Luster
Pearly
Streak
White
Density
2.43
Cleavage
Perfect on {001}
Fracture
Uneven
Transparency
Transparent to translucent
Crystal system
Orthorhombic

Diagnostic features

## Identification Identifying kenotobermorite under amateur conditions is practically impossible. It requires advanced analytical methods such as X-ray diffraction (XRD) or spectroscopy. Visually, it can be suspected based on its form – small, white, bladed crystals with a pearly luster, occurring in a specific geological environment. ## Distinguishing from Similar Minerals It can be confused with other minerals from the tobermorite group (tobermorite, clinotobermorite), as well as other white fibrous silicates such as wollastonite or some zeolites. Definitive distinction is only possible through laboratory analysis. ## Crystal Forms Kenotobermorite forms elongated, bladed, or acicular crystals. They usually occur as radial, spherulitic, or haphazardly entangled aggregates.

Geological environment

## Genesis Kenotobermorite is a low-temperature hydrothermal mineral. It forms as a result of metasomatic alteration of carbonate rocks (limestones, marbles) under the influence of silica-rich solutions. It is a component of skarns and other contact-metamorphic rocks. ## Mineral Associations It most often co-occurs with calcite, wollastonite, apophyllite, and other minerals from the tobermorite group. ## Localities The most important occurrences of this mineral are in the Hatrurim complex in Israel (type locality), as well as in Jordan. It has also been identified in the Wessels Mine in Kuruman (Northern Cape Province, South Africa) and in the N’Chwaning Mines in South Africa.

Rarity

Very rare

For collectors

## Quality Criteria Due to the microscopic size of the crystals, kenotobermorite specimens are primarily evaluated based on the richness and aesthetics of the aggregates. The most prized specimens are those with well-formed, spherulitic or radial clusters on a contrasting matrix. The purity and size of individual crystals, although still microscopic, also increase the value of the specimen. ## Popular Localities The most well-known specimens, available on the collector's market, come from mines in the Kuruman area of South Africa, where this mineral forms visually attractive aggregates.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using only a soft brush to remove dust. Due to its brittleness and small crystal size, avoid washing with water, and especially avoid using ultrasonic cleaners, which can damage delicate aggregates. ## What to Avoid Avoid contact with acids and other chemicals. The mineral is susceptible to mechanical damage, so protect it from impacts, scratches, and vibrations. Do not heat it or expose it to rapid temperature changes. ## Storage Kenotobermorite specimens are best stored in sealed "micromount" boxes, which protect them from dust and mechanical damage. Avoid exposure to direct sunlight, although its effect on the mineral is not known.

External references

Sources

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