Katayamalite
Chemical formula: KLi<sub>3</sub>Ca<sub>7</sub>Ti<sup>4+</sup><sub>2</sub>(SiO<sub>3</sub>)<sub>12</sub>(OH)<sub>2</sub>
Katayamalite is an extremely rare, purple potassium, lithium, calcium, and titanium silicate, forming small, bladed crystals in syenitic pegmatites.
Properties
- Mohs hardness
- 5.5-6
- Luster
- Vitreous
- Streak
- White
- Density
- 3.01
- Cleavage
- Perfect on {100}
- Fracture
- Uneven
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Field identification of katayamalite is practically impossible due to its extreme rarity and small crystal size. Identification requires advanced laboratory methods, such as X-ray diffraction (XRD) and chemical analysis (EDS/WDS). In a collection, it can be preliminarily identified based on its characteristic light purple color, bladed crystal habit, and confirmed locality (Iwagi Island). ## Distinguishing from Similar Minerals Due to its unique appearance and extreme rarity, it is practically not confused with other minerals, especially when its origin is known. Theoretically, some purple minerals with a fibrous habit could be similar, but katayamalite is distinguished by its specific geological environment and associated minerals. ## Crystal Forms It forms elongated, bladed or acicular crystals, often grouped into radial or tangled aggregates. Crystals are very small, usually less than 1 mm in length.
Geological environment
## Genesis Katayamalite forms under specific geological conditions, within syenitic pegmatites. Its occurrence is associated with metasomatic processes, where hot, element-rich solutions react with the surrounding rock, leading to the crystallization of rare minerals. ## Mineral Associations This mineral co-occurs with other rare minerals at its discovery site. It is most commonly associated with aegirine, microcline, albite, quartz, titanite, ekanite, mongolite, as well as the newly discovered iwagiite and watatsumiite. ## Localities The only confirmed locality of katayamalite in the world is its type locality – Iwagi Island, Ehime Prefecture, Japan. It is an endemic mineral to this single, small occurrence.
Rarity
Extremely rare
For collectors
## Quality Criteria The quality of a katayamalite specimen primarily depends on the richness and visibility of the purple crystals on the rock matrix. The most prized specimens are those with numerous, well-formed, and intensely colored crystal aggregates, contrasting with the light background of the rock (usually albite or microcline). The size of the crystals, even if only a fraction of a millimeter, also increases value. ## Popular Localities All specimens available on the collector's market come from a single location in the world – Iwagi Island, Japan. This is the only known locality for this mineral.
Care and storage
## Cleaning Katayamalite specimens are extremely delicate and small, so mechanical cleaning should be avoided. If absolutely necessary, compressed air can be used to remove dust. Contact with water and any chemicals should be avoided. ## What to Avoid Avoid ultrasonic cleaners, acids, solvents, and sudden temperature changes. The mineral is sensitive to shocks and impacts, which can damage the delicate crystals. ## Storage It is recommended to store specimens exclusively in specialized, sealed "micromount" boxes, which protect against dust and mechanical damage. Avoid exposure to direct sunlight, although there is no evidence of fading.