Calcioancylite-(Nd)
Chemical formula: Nd₂.₈Ca₁.₂(CO₃)₄(OH)₃·H₂O
Calcioancylite-(Nd) is a rare mineral from the carbonate group, distinguished by its high neodymium content and occurrence as small, pinkish crystals.
Properties
- Mohs hardness
- 4-4.5
- Color
- Pale pink
- Luster
- Vitreous
- Streak
- White
- Density
- 4.02
- Cleavage
- Good on {110}
- Fracture
- Irregular/Uneven
- Transparency
- Transparent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Amateur identification of calcioancylite-(Nd) is practically impossible due to its small size and resemblance to other minerals of the ancylite group. Definitive identification requires advanced analytical methods, such as EDS spectroscopy or electron microprobe (EMPA), to confirm the chemical composition with dominant neodymium and calcium. ## Distinguishing from Similar Minerals It can be confused with other minerals from the same group, such as ancylite-(Ce), ancylite-(La), or calcioancylite-(Ce). They differ in the dominant rare earth element, which is impossible to determine without specialized analysis. Visually, it may also resemble other small, pink secondary minerals. ## Crystal Forms Crystals are most often prismatic, elongated, terminated by rhombohedral or dipyramidal faces. They occur as single, grown crystals or in small, loose groups.
Geological environment
## Genesis It is a hydrothermal mineral, crystallizing in the late stage from solutions rich in rare earth elements and carbonates. It forms in vugs and fissures in granites and syenites, often in Alpine-type pegmatites. ## Mineral Associations It most commonly co-occurs with quartz, orthoclase, albite, mica, as well as other rare minerals such as ewaldite, synchysite, bastnäsite, cordylite, burbankite, or fluorite. ## Localities The most important and classic localities for this mineral are the granite quarry in Baveno, Piedmont, Italy (type locality), and the Khibiny Massif on the Kola Peninsula in Russia. It has also been reported in Norway and Canada (Mont Saint-Hilaire).
Rarity
Very rare
For collectors
## Quality Criteria Most valued by collectors (mainly those specializing in "micromounts") are specimens with well-formed, sharp crystals of intense, pink coloration. Contrast with the matrix mineral on which the crystals are embedded, and the presence of associated minerals, are important. The size of the crystals, even if exceeding 1 mm, significantly increases the value of the specimen.
Care and storage
## Cleaning Specimens should only be cleaned very carefully, using a soft brush to remove dust. Due to the small size of the crystals and their brittleness, wet or mechanical cleaning is not recommended. ## What to Avoid Contact with acids, which cause vigorous effervescence and decomposition of the mineral, must be absolutely avoided. Avoid ultrasonics, steam cleaners, and strong detergents. The mineral is brittle, so it should be protected from impacts and scratching. ## Storage It is recommended to store specimens in sealed "micromount" boxes, which protect them from dust, mechanical damage, and sudden changes in humidity.