Murakamiite

Chemical formula: Ca<sub>2</sub>LiSi<sub>3</sub>O<sub>8</sub>(OH)

Murakamiite is a very rare mineral from the pectolite group, discovered in Japan, forming colorless, bladed crystals with a vitreous luster.

## Characteristics Murakamiite is a calcium lithium silicate belonging to the pectolite group. This mineral forms aggregates of small, bladed or fibrous crystals, which typically do not exceed 1 mm in length. Individual crystals are colorless and transparent, while their aggregates are white and have a silky luster. ## Physical Properties Murakamiite crystals exhibit a hardness of approximately 5 on the Mohs scale. They have a vitreous luster, and in aggregates, a silky luster. They are transparent, with a white streak. The mineral's density is approximately 2.83 g/cm³. ## History and Name The mineral was approved by the IMA in 2016. Its name honors Akihiko Murakami (born 1948), a Japanese amateur mineralogist who discovered many new minerals, including the type specimen of murakamiite. The discovery was made on Iwagi Island, Ehime Prefecture, Japan.

Properties

Mohs hardness
5
Luster
Vitreous, Silky
Streak
White
Density
2.83
Cleavage
Perfect on {100} and {001}
Fracture
Splintery
Transparency
Transparent
Crystal system
Triclinic

Diagnostic features

## Identification Identifying murakamiite is extremely difficult without advanced analytical methods such as Raman spectroscopy or X-ray diffraction (XRD). Preliminary identification is based on crystal habit (small, bladed, colorless aggregates), co-occurrence with other minerals (sugilite, pectolite), and locality. ## Distinguishing from similar minerals Murakamiite is visually indistinguishable from other white, fibrous minerals of the pectolite group, such as pectolite itself or serandite. It differs from them in chemical composition, particularly the presence of lithium, which requires laboratory confirmation. ## Crystal forms Murakamiite forms elongated, bladed crystals, often gathered in radial or tangled aggregates. The crystals are very small, usually less than 1 mm in size.

Geological environment

## Genesis Murakamiite forms within syenite pegmatites that intruded amphibolite rocks. It is a product of hydrothermal processes occurring in the late stage of crystallization of these pegmatites. ## Mineral associations This mineral co-occurs with pectolite, sugilite, aegirine, albite, microcline, and quartz. ## Localities The only confirmed occurrence of murakamiite in the world is its type locality – a syenite pegmatite on Iwagi Island, Ehime Prefecture, Japan.

Rarity

Extremely rare

For collectors

## Quality criteria As a "micromount" type mineral, the collector's value of murakamiite primarily depends on the richness and development of crystals in the aggregate, as well as their association with other rare minerals, such as sugilite. Any specimen with confirmed identity is extremely valuable due to the mineral's extreme rarity. ## Popular localities The only source of specimens is the type locality in Japan, which makes them practically unavailable on the collector's market.

Care and storage

## Cleaning Due to its extreme rarity and delicacy, murakamiite specimens should be cleaned only when absolutely necessary, using compressed air to remove dust. Contact with water and chemicals should be avoided. ## What to avoid Avoid ultrasonic cleaners, chemical agents, acids, and sudden temperature changes. The mineral is brittle and susceptible to mechanical damage. ## Storage Specimens should be stored in stable conditions, in a sealed "micromount" box, protecting them from dust, moisture, and direct sunlight. Due to the small size of the crystals, particular caution is recommended during handling.

Sources

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