Parisite-(Ce)
Chemical formula: (Ca,Ce)₂((Ce,La)₂(CO₃)₃F₂)
Parisite-(Ce) is a rare calcium cerium fluorocarbonate mineral, typically forming hexagonal crystals with a yellow to brown color.
Description
## Characteristics Parisite-(Ce) is a carbonate group mineral, characterized by the presence of rare earth elements, primarily cerium. It most commonly occurs as hexagonal, prismatic or tabular crystals, often with distinct striations. Its color ranges from pale yellow, through honey-yellow, to brown, and sometimes even reddish-brown. Crystals can be transparent to translucent, with a distinct luster. Parisite-(Ce) aggregates can be massive or radial. ## Physical Properties Parisite-(Ce) has a Mohs hardness of 4.5. It exhibits a vitreous to resinous luster. It is transparent to translucent. The mineral's density is approximately 4.3-4.4 g/cm³. ## Colors and Varieties Typical colors of parisite-(Ce) include yellow, honey-yellow, brown, and reddish-brown. The intensity of the color can depend on the content of rare earth element impurities. There are no widely known commercial varieties of parisite-(Ce), but its color is significant for collectors. ## History and Name The mineral was discovered in 1845 in the emerald mine in Muzo, Colombia. The name "parisite" comes from the surname of J.J. Paris, the owner of the mine where the mineral was first found. ## Uses Parisite-(Ce) is primarily a mineral of collector's interest. Due to its rare earth element content, it could theoretically be a source of these elements; however, its rarity and limited occurrence mean it has no economic significance as an ore.
Diagnostic features
## Identification Parisite-(Ce) can be identified by its hexagonal crystal habit, often with distinct striations on the prism faces. Its characteristic color – from yellow to brown – and vitreous to resinous luster are also diagnostic. A Mohs hardness of 4.5 is also a diagnostic feature. ## Distinguishing from Similar Minerals Parisite-(Ce) is sometimes confused with other rare earth-bearing carbonate minerals, such as bastnäsite-(Ce) or synchysite-(Ce). It differs from them in chemical composition and detailed crystal structure. It is distinguished from bastnäsite-(Ce) by the presence of calcium in its chemical composition. It differs from synchysite-(Ce) by having a double layer of calcium and cerium carbonate, whereas synchysite-(Ce) has a single layer. ## Crystal Forms Parisite-(Ce) most commonly forms hexagonal, prismatic or tabular crystals. Twinning is often observed. Horizontal striations are often visible on the prism faces. It can also form radial or massive aggregates.
Geological environment
## Genesis Parisite-(Ce) is a hydrothermal mineral, forming at low to medium temperatures. It occurs in hydrothermal veins, often associated with alkaline intrusions and in carbonatite deposits. It can also form in pegmatites and metamorphic rocks. ## Mineral Associations Parisite-(Ce) often co-occurs with other rare earth-bearing minerals, such as bastnäsite-(Ce), synchysite-(Ce), fluorite, ankerite, calcite, quartz, as well as minerals like pyrochlore and monazite-(Ce). ## Localities The most famous localities for parisite-(Ce) include the emerald mine in Muzo, Colombia, where it was discovered. Other important occurrences include Mont Saint-Hilaire in Quebec (Canada), Langesundsfjord in Norway, the Kola Peninsula in Russia, as well as some localities in the USA (Montana, Arkansas) and Africa (Congo, Tanzania).
Rarity
Rare
Collector aspects
## Quality Criteria The most prized parisite-(Ce) specimens are well-formed, hexagonal crystals with intense, uniform color (especially honey-yellow or brown) and high transparency. Large, undamaged crystals with distinct luster are particularly sought after. Specimens with aesthetic associations with other minerals also increase their collector's value. ## Popular Localities The most prized parisite-(Ce) specimens come from Colombia (Muzo), where they occur in association with emeralds. Specimens from Mont Saint-Hilaire in Canada are also highly valued due to their quality and variety of crystal forms.
Care and storage
## Cleaning Parisite-(Ce) specimens should be cleaned gently, using a soft brush and lukewarm water. Distilled water can be used to avoid mineral deposits. Avoid vigorous rubbing, which could scratch the mineral's surface. ## What to Avoid Parisite-(Ce) should not be exposed to strong acids, which can damage it. Also, avoid sudden temperature changes and prolonged exposure to direct sunlight, which can lead to color changes. The mineral is quite brittle, so it should be protected from impacts. ## Storage Parisite-(Ce) is best stored in closed display cases or boxes, away from dust and humidity. It is advisable to place it on a soft surface to prevent mechanical damage. Highly transparent and intensely colored specimens should be protected from light.