Chernovite-(Y)
Chemical formula: YAs<sup>5+</sup>O<sub>4</sub>
Chernovite-(Y) is a rare yttrium arsenate, prized by collectors for its well-formed, lustrous crystals of intense color.
Properties
- Mohs hardness
- 4-5
- Luster
- Vitreous, Adamantine
- Streak
- White
- Density
- 5.36
- Cleavage
- Good on {100}
- Fracture
- Uneven
- Transparency
- Transparent, Translucent
- Crystal system
- Tetragonal
Diagnostic features
## Identification Chernovite-(Y) can be identified by its characteristic tetragonal crystal habit, intense yellow or green color, and strong, vitreous luster. It is relatively hard and heavy for its size. It occurs in a specific geological environment. ## Distinguishing from Similar Minerals It can be confused with other minerals from the xenotime group, such as xenotime-(Y) or wakefieldite-(Y). Definitive differentiation requires advanced chemical analyses (EDS/WDS) to confirm the dominance of arsenic. Visually, it may resemble some varieties of sphalerite, scheelite, or even native sulfur, but it differs from them in crystal habit, hardness, and occurrence environment. ## Crystal Forms It forms simple, tetragonal crystals with a dipyramidal or prismatic habit, often terminated by a pyramid. Crystals are usually small, rarely exceeding a few millimeters, but can be perfectly formed. It occurs as single crystals or small aggregates.
Geological environment
## Genesis Chernovite-(Y) is a hydrothermal mineral. It forms in the oxidation zones of ore deposits, often in quartz veins or in cavities within carbonate rocks. Its crystallization is associated with the presence of yttrium- and arsenic-rich solutions. ## Mineral Associations It most commonly co-occurs with quartz, barite, fluorite, galena, sphalerite, chalcopyrite, as well as other rare arsenates and rare earth minerals, such as agardite, xenotime-(Y), and wakefieldite-(Y). ## Localities The most important and classic locality for this mineral is the Berezovskoe deposit in the Urals, Russia. It is also known from the Příbram mine in the Czech Republic, from Saxony in Germany (e.g., Clara mine), from the Tsumeb mine in Namibia, and from several localities in Switzerland (e.g., Val d'Anniviers).
Rarity
Rare
For collectors
## Quality Criteria Specimens with sharp, well-formed, lustrous crystals of intense, saturated color (especially bright yellow or green) are most highly valued. It is important that the crystals are undamaged and aesthetically set on a small, contrasting rock matrix. Crystal size is significant – specimens with crystals exceeding 2-3 mm are considered exceptional. ## Popular Localities The most sought-after specimens by collectors come from historical localities in Germany (Clara mine) and the Czech Republic (Příbram), which have yielded some of the world's best crystals of this mineral. Specimens from the Urals in Russia are also classics for this species.
Care and storage
## Cleaning Specimens should only be cleaned mechanically, using a soft brush to remove dust. For heavier soiling, compressed air can be used. Avoid contact with water and all chemicals. ## What to Avoid Chernovite-(Y) is sensitive to acids, which can damage it. Avoid ultrasonic cleaners, sudden temperature changes, and prolonged exposure to direct sunlight, which can cause color fading. ## Storage It is recommended to store specimens in stable conditions, in separate, padded boxes to prevent scratches and mechanical damage. It is best to keep them away from moisture and heat sources.