Description
Bastnaesite, often written Bastnäsite, is a cerium fluoride carbonate, CeCO3(OH,F), found in contact metamorphic zones and pegmatites; light rare earth, lanthanum, yttrium, and thorium are typically replaced for cerium. Its color ranges from waxy yellow to reddish-brown. Bastnaesite is frequently found with other rare-earth-bearing minerals such as allanite, cerite, and tysonite, and is frequently a tysonite alteration result. Bastnaesite may be found in pegmatites at Pikes Peak, Colorado, and in Lincoln County, New Mexico, where it is commercially mined.
General Information
| Category | Carbonate mineral |
| Formula | (La, Ce, Y)CO3F |
| Crystal system | Hexagonal |
| Crystal class | Ditrigonal dipyramidal (6m2) |
History
Bastnäsite is named after the Bastnäs Mine in Riddarhyttan, Västmanland, Sweden, where it was discovered. Swedish scientists Jöns Jakob Berzelius, Wilhelm Hisinger, and Carl Gustav Mosander discovered many new minerals and chemical elements using ore from the Bastnäs Mine. The chemical elements cerium, which was discovered by Hisinger in 1803, and lanthanum, which was discovered in 1839, is among them. When one of the new minerals was initially identified by Hisinger in 1838, he named it bastnäsit, as he was also the proprietor of the Bastnäs mine.
PHYSICAL CHARACTERISTICS
- Cleavage: {1011} Imperfect, {0001} Indistinct
- Color: yellow, reddish brown.
- Density: 4.95 – 5, Average = 4.97
- Diaphaneity: Transparent to Translucent
- Fracture: Uneven – Flat surfaces (not cleavage) fracture in an uneven pattern.
- Hardness: 4-5 – Fluorite-Apatite
- Luminescence: Non-fluorescent.
- Luster: Vitreous – Greasy
- Streak: white
- Tenacity: Brittle
Where Is It From?
Bastnaesite is a rare earth carbonate mineral that occurs in just a few places on the planet. This mineral was found in Sweden in 1838 and called for the mine where it was discovered. It was also discovered at the Paratoo copper mine in South Australia. It can form as flat transparent crystals, tabular crystals, or thin plates, and its hue is often honey-golden or reddish-brown. Beautiful better quality crystals with a magnificent form and vibrant orange-red hue have just emerged from Pakistan and may be found by browsing the internet.
Composition
Bastnasite’s generalized formula contains cerium, lanthanum, and yttrium, although the mineral is legally separated into three minerals based on the main rare earth element. Bastnasite-(Ce) has the more precise formula of (Ce, La)CO3F. Bastnasite-(La) is a mineral having the formula (La, Ce)CO3F. Then there’s Bastnasite-(Y), which has the formula (Y, Ce)CO3F. In terms of physical qualities, there is little difference between the three, and most bastnasite is bastnasite-like (Ce). Cerium generally exceeds the other elements in most natural bastnasites. Cerium, an essential industrial metal, is found mostly in bastnasite and the phosphate mineral monazite.
Bastnasite is a mineral that is closely linked to parisite. Both are rare earth fluorocarbonates, but parisite has a calcium atom and a distinct ratio of component ions in its formula of Ca(Ce, La, Nd)2(CO3)3F2. Parisite is made up of two molecules of bastnasite and one molecule of calcite (CaCO3). In fact, in natural situations, the two have been found to switch back and forth with the addition or removal of CaCO3. With the mineral hydroxylbasnasite, bastnasite forms a series.
