Chevkinite-(Ce)
Chevkinite-(Ce) is a REE that is rareRare Earth Element) titano-silicate mineral that is weakly radioactive because of its almost 2% thorium (Th) content. Chevnikite-(Ce) provides the planet that is unusual cerium (Ce) and Lanthanum (La). It really is found as opaque, dark reddish brown to black colored prismatic crystals with resinous to luster that is sub-metallic Moh’s hardness of 5.5-6.0.
Chevkinite-(Ce) ended up being found in 1839 during the Pit No. 17, Ilmen Natural Reserve, Ilmen Mts, Chelyabinsk Oblast’, Southern Urals, Urals Region, Russia. It ended up being named by Gustav Rose in honor of General-Major Konstantin Vladimirovich Tschevkin [Chevkin] (1802-1875), Chief of Staff of the Russian Mining Engineers Corps; and its Cerium (Ce) content.
Chevkinite-(Ce) circulation: from the Ilmen Mountains, Southern Ural Mountains; the Keivy massif, Kola Peninsula; and elsewhere in Russia. At Buer, Björkedalen, Norway. From Glen Bay, Na h-Eagan, and Conachair, in the Isles of St. Kilda, Outer Hebrides, Scotland. In Madagascar, through the Tordendrika-Ifasina area, Androngovato, and Ifasina, Ambatofinandrahana. From the Chilas area, near Nanga Parbat, Pakistan. In the USA, in the Aquarius Mountains, Mohave County, Arizona; the Jemez Mountains and Pueblo Mesa, Rio Arriba County, New Mexico; at Onion Creek, Grand County, Utah; in Yellowstone National Park, Wyoming; from Irish Flats, Meade County, Kansas. Also within the Spruce Pine region, Mitchell County, vermont; near Martin’s shop, Nelson County, Virginia; plus in New Hampshire, from near Stark, Coos County. A couple of other localities have been verified.
| Chemical Formula: | (Ce,La,Ca,Th)4(Fe2+,Mg)(Fe2+,Ti,Fe3+)2(Ti,Fe3+)2(Si2O7)2O8 |
| Cerium Lanthanum Calcium Thorium Iron Magnesium Titanium Silicate | |
| Molecular Weight: | 1,205.27 gm |
| Composition: | Calcium | 2.66 % | Ca | 3.72 % | CaO |
| Lanthanum | 16.13 % | La | 18.92 % | La2O3 | |
| Cerium | 19.76 % | Ce | 23.15 % | Ce2O3 | |
| Thorium | 1.93 % | Th | 2.19 % | ThO2 | |
| Magnesium | 0.40 % | Mg | 0.67 % | MgO | |
| Titanium | 9.93 % | Ti | 16.57 % | TiO2 | |
| Iron | 10.66 % | Fe | 10.73 % | FeO / 3.31 % Fe2O3 | |
| Silicon | 9.32 % | Si | 19.94 % | SiO2 | |
| Oxygen | 29.20 % | O | |||
| 100.00 % | 99.20 % | = TOTAL OXIDE |
| Crystallography: | Monoclinic – Prismatic |
| Crystal Habit: | Small lamellar, lenticular, and prismatic crystals; massive, in lumps to 10 cm. |
| Twinning: | Twin plane {001} |
| Cleavage: | None |
| Fracture: | Irregular/uneven to Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 5.5 – 6.0 |
| Density: | 4.53 – 4.67 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Weak; GRapi = 37,661.04 (Gamma Ray American Petroleum Institute Units) |
| Health Warning: | Contains thorium – always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest. Avoid prolonged exposure in proximity of the body. Store away from inhabited areas. |
| Color: | Dark reddish brown to black; red to orange-brown inner reflections |
| Transparency: | Opaque except on thin edges |
| Luster: | Resinous to dull |
| Refractive Index: | 1.967 – 2.050 Biaxial ( – ) |
| Birefringence: | 0.077 – 0.083 |
| Dispersion: | Distinct to strong; r < v |
| Pleochroism: | X = almost colorless; Y = reddish brown; Z = dark brown |
