Hingganite

Chemical formula: Be₂Y₂(SiO₄)₂(OH)₂

A rare mineral from the gadolinite group, forming small, vitreous crystals ranging in color from green to brown, prized by collectors.

## Characteristics Hingganite is a rare mineral belonging to the gadolinite group. It occurs as small, prismatic or acicular crystals, often forming radial or fan-shaped aggregates. Specimens typically have a vitreous luster and can be transparent. Due to the small size of its crystals, it is a mineral primarily valued by specialized collectors. ## Physical Properties Hingganite crystals are brittle. The mineral has a hardness ranging from 5-6 on the Mohs scale and a density of 4.23 to 4.85 g/cm³. The luster is typically vitreous, and on fracture surfaces, it can be greasy. It is transparent to translucent. ## Colors and Varieties The most common colors are various shades of green (from pale green, through grayish-green, to yellowish-green), brown, and gray. Colorless, white, and even pink specimens are also known. Varieties rich in yttrium (hingganite-(Y)), ytterbium (hingganite-(Yb)), and cerium (hingganite-(Ce)) are distinguished, which are separate minerals within the group but visually almost identical. ## History and Name The mineral's name comes from its type locality – the Greater Khingan Mountains (Da Hinggan Ling) in Inner Mongolia (China). It was described and approved as a new mineral species in 1981 by X. Ding, G. Bai, Z. Liu, and Z. Tian. ## Uses Due to its rarity and small crystal size, hingganite has no industrial applications. It is solely an object of interest for collectors and scientists.

Properties

Mohs hardness: 5-6
Luster: Vitreous, Greasy
Streak: White
Density: 4.23-4.85
Cleavage: Good on {110}
Fracture: Uneven, Conchoidal
Transparency: Transparent to Translucent
Crystal system: Monoclinic

Diagnostic features

## Identification Hingganite is difficult to identify visually without specialized equipment. Helpful features include: monoclinic crystal system, characteristic radial aggregates of acicular crystals, vitreous luster, and occurrence in specific geological environments (granitic pegmatites, skarns). ## Distinguishing from Similar Minerals It can be confused with other minerals from the gadolinite group (datolite, gadolinite), as well as vesuvianite, epidote, or tourmaline. Definitive differentiation requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS/WDS), due to the similarity in physical properties and crystal forms. ## Crystal Forms Crystals are typically elongated, prismatic, often terminated by a bipyramid. They form characteristic aggregates with a radial, spherulitic, or fan-shaped habit. They also occur as granular masses.

Geological environment

## Genesis Hingganite is a mineral of magmatic or metamorphic origin. It forms in the late stages of crystallization of granitic pegmatites, especially those rich in rare earth elements. It is also found in skarns formed at the contact of granitic intrusions with carbonate sedimentary rocks. ## Mineral Associations It often co-occurs with minerals such as: quartz, microcline, albite, fluorite, topaz, cassiterite, gadolinite, allanite, zircon, titanite, and other rare earth minerals. ## Localities The most important localities worldwide include the Greater Khingan Mountains in China (type locality), numerous pegmatites in Norway (e.g., Tysfjord, Langesundsfjorden), Sweden, Russia (Kola Peninsula), as well as in the USA (Colorado, Wisconsin), Canada (Quebec, Ontario), Japan, and Italy.

Rarity

Rare

For collectors

## Quality Criteria The most prized specimens by collectors are those with well-formed, sharp, and undamaged crystals, forming aesthetic, radial aggregates. An intense, attractive color (e.g., vivid green) and transparency are important. A contrasting association with accompanying minerals (e.g., on white albite or quartz) significantly increases the specimen's value. ## Popular Localities The best quality specimens come from pegmatites in Norway (especially the Tysfjord region), Canada (e.g., the Evans-Lou mine in Quebec, where large, well-formed crystals were found), and some localities in Russia.

Care and storage

## Cleaning Specimens should be cleaned very carefully, using a soft brush to remove dust. If necessary, distilled water can be used, but prolonged soaking should be avoided. Ultrasonic cleaners are not recommended, as they can damage delicate crystals. ## What to Avoid Avoid contact with acids and strong chemicals. The mineral is brittle, so it must be protected from impacts and drops. Some specimens may be sensitive to sudden temperature changes. ## Storage It is best to store specimens in individual, padded collector's boxes to prevent abrasions and mechanical damage. They should be protected from dust and moisture.

Sources

IMA Mineral List (CNMNC)