Zoharite

Chemical formula: (Ba,K)₆(Fe,Cu,Ni)₂₅S₂₇

Zoharyite is an extremely rare sulfide containing barium, potassium, iron, copper, and nickel, occurring as metallic, black grains.

## Characteristics Zoharyite is a very rare mineral from the sulfide group, identified based on microscopic, irregular grains not exceeding 0.1 mm in size. In reflected light, its color is gray, with a noticeable brownish tint. It is an opaque mineral with a metallic luster. ## Physical Properties Due to the small size of the grains, most physical properties, such as hardness, density, or fracture, have not been precisely determined. The hardness (VHN) measured for one grain was 203, which approximately corresponds to a value of about 4 on the Mohs scale. ## History and Name The mineral was discovered in the Hatrurim Formation in Israel, known for its unique pyrometamorphic geology. Its name honors Efraim Zohar (1910-1994), an Israeli geologist and director of the Israel Geological Survey, for his contribution to geological research in Israel. It was approved by the International Mineralogical Association (IMA) in 2016 under number 2016-018.

Properties

Mohs hardness: ~4
Luster: Metallic
Streak: Black
Transparency: Opaque
Crystal system: Cubic

Diagnostic features

## Identification Identification of zoharyite is possible only through advanced laboratory methods, such as chemical composition analysis using an electron microprobe (EDS/WDS) and electron backscatter diffraction (EBSD) to determine the crystal structure. Visual identification is impossible. ## Distinguishing from Similar Minerals Distinguishing it from other rare, opaque sulfides with a metallic luster, such as polydymite or other minerals from the lincolnite group, requires specialized chemical and crystallographic analysis. ## Crystal Forms Zoharyite occurs exclusively as anhedral (irregular), irregular grains up to 100 micrometers in size.

Geological environment

## Genesis Zoharyite forms under specific conditions of pyrometamorphism, i.e., the transformation of rocks under very high temperature but low pressure. It was found in a host rock consisting mainly of larnite, ye'elimite, and brownmillerite, formed as a result of combustion and recrystallization of marly sediments. ## Mineral Associations This mineral co-occurs with other rare minerals formed under similar conditions, such as gupeiite, xifengite, trüstedtite, cuproiridsite, as well as with more common rock-forming minerals of the Hatrurim Formation, such as larnite, ye'elimite, and brownmillerite. ## Localities The only confirmed locality of zoharyite in the world is its type locality - the Hatrurim Formation in the Judean Desert, Israel.

Rarity

Extremely rare

For collectors

## Quality Criteria Zoharyite does not occur in macroscopic specimens, and its value is purely scientific. The only criterion is the confirmation of its presence in a rock sample using analytical methods. Specimens take the form of polished sections for microscopic examination or fragments of the host rock in which the mineral was identified.

Care and storage

## Cleaning Due to its extreme rarity and microscopic grain size, zoharyite specimens are not subject to cleaning in the traditional sense. Any manipulations should be carried out only under laboratory conditions by specialists. ## What to Avoid Contact with chemicals, moisture, and any mechanical factors that could damage or destroy the microscopic grains embedded in the host rock should be avoided. ## Storage Specimens containing zoharyite should be stored under stable conditions, in specialized containers protecting against dust, moisture, and mechanical damage, preferably in archival conditions.

Sources

IMA Mineral List (CNMNC)