Yttrotungstite-(Ce)

Chemical formula: Ce³⁺W⁶⁺₂O₆(OH)₃

Yttrotungstite-(Ce) is a rare tungsten and cerium hydroxide, forming small, yellow to greenish crystals and coatings.

## Characteristics Yttrotungstite-(Ce) is a mineral from the tungstate group, chemically classified as a tungsten and cerium hydroxide. It occurs as very small, bladed or tabular crystals, rarely exceeding 1 mm in length. Most often, it forms radial aggregates, rosettes, as well as earthy or powdery coatings and crusts on other minerals. ## Physical Properties Crystals exhibit an adamantine to resinous luster, while aggregates are dull or earthy. The mineral is translucent. Its Mohs hardness is approximately 3, and its density ranges from 6.5 to 6.6 g/cm³. ## Colors and Varieties Yttrotungstite-(Ce) has a characteristic range of colors, from canary yellow, through yellowish-green, to olive-green. No varieties have been distinguished. ## History and Name The mineral's name refers to its chemical composition – the dominance of yttrium and tungsten in the original yttrotungstite. The suffix "-(Ce)" indicates that in this particular mineral, cerium is the dominant rare earth element in a specific crystallographic site. It was recognized by the International Mineralogical Association (IMA) in 1987.

Properties

Mohs hardness: 1
Color: Orange-yellow
Luster: Adamantine, Resinous, Dull, Earthy
Streak: Light yellow
Density: 0
Cleavage: On {100}, perfect.
Fracture: Uneven
Transparency: Translucent
Crystal system: Monoclinic

Diagnostic features

## Identification The mineral is identified by its characteristic yellow to greenish color, occurrence as fine, radial aggregates or earthy coatings, and by its environment of occurrence – oxidation zones of tungsten deposits. Due to the small size of the crystals, definitive identification requires advanced analytical methods such as X-ray diffraction (XRD) or chemical analysis (EDS/WDS). ## Distinguishing from Similar Minerals It can be confused with other secondary tungsten minerals of similar colors, such as scheelite, stolzite, or tungstite. Distinguishing it from these with the naked eye is practically impossible and requires specialized research equipment. Its high density can be a helpful clue, but it is difficult to measure on such small samples. ## Crystal Forms It forms very small, bladed or tabular crystals, usually grouped into radial aggregates, rosettes, or spherulites. It often occurs as earthy and powdery coatings.

Geological environment

## Genesis Yttrotungstite-(Ce) is a secondary mineral formed in the oxidation (weathering) zones of hydrothermal tungsten deposits, especially those rich in rare earth elements. It forms as a result of the alteration of primary tungsten minerals, such as wolframite or scheelite. ## Mineral Associations It often co-occurs with minerals such as quartz, wolframite, scheelite, ferberite, as well as other secondary tungsten and cerium minerals. ## Localities The most important and best-documented locality, which is also the type locality, is the Kramat Pulai mine in Perak State, Malaysia. This is the main locality from which specimens of this mineral originate.

Rarity

Very rare

For collectors

## Quality Criteria The collector's appeal of a specimen depends on the intensity and purity of the yellow or green color, as well as the richness and visibility of the coatings on the host rock. Samples with clearly formed, albeit microscopic, crystalline aggregates, rather than just an earthy coating, are most valued. Due to its rarity, any well-documented specimen has value for specialized collectors. ## Popular Localities The only significant source of collector specimens is the historical type locality – the Kramat Pulai mine in Malaysia.

Care and storage

## Cleaning Due to its fragility and occurrence as fine coatings, mechanical cleaning is highly risky. If absolutely necessary, compressed air can be used to remove dust. Contact with water and all chemicals should be avoided. ## What to Avoid Avoid ultrasonic cleaners, chemical agents (acids and bases), high temperatures, and humidity. The mineral is very soft and brittle, susceptible to scratches and mechanical damage. ## Storage Yttrotungstite-(Ce) specimens should be stored under stable conditions, in closed collector boxes, to protect them from dust, humidity, and physical damage. They should be kept away from minerals that could scratch them.

External references

https://www.mindat.org/min-7380.html