سمارسكيت-(إ)
| Samarskite-(Y) | |
|---|---|
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| العامة | |
| التصنيف | معادن أكاسيد |
| الصيغة (repeating unit) | (YFe3+Fe2+U,Th,Ca) 2(Nb,Ta) 2O 8 |
| تصنيف سترونز | 4.DB.25 |
| النظام البلوري | Orthorhombic |
| Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
| Space group | Pbcn |
| Unit cell | a = 5.687 Å, b = 4.925 Å c = 5.21 Å; Z = 2 |
| التعرف | |
| Color | Black, may have a brownish tint, brown to yellowish brown due to alteration; light to dark brown in transmitted light |
| Crystal habit | Crystals elongated with pyramidal terminations; commonly granular to massive |
| Cleavage | {010}, indistinct |
| Fracture | Conchoidal fragments |
| Tenacity | Brittle |
| Mohs scale hardness | 5–6 |
| Luster | Vitreous – resinous |
| Streak | بني مائل للحمرة |
| Diaphaneity | Opaque, transparent in thin fragments |
| الكثافة | 5.6 – 5.8, Average = 5.69 |
| الصفات البصرية | Appears isotropic |
| Refractive index | n = 2.1–2.2 |
| تتحول إلى | Metamict |
| سمات أخرى |  Radioactive (Greater than 70 Bq / gram) |
| References | [1][2][3][4] |
سمارسكيت Samarskite هو سلسلة من المعادن الأرضية النادرة المشعة التي تضم سمارسكيت-(إ)، بالصيغة الكيميائية (YFe3+Fe2+U,Th,Ca)
2(Nb,Ta)
2O
8[2] and samarskite-(Yb), with the chemical formula (YbFe3+)
2(Nb,Ta)
2O
8.[6] The formula for samarskite-(Y) is also given as (Y,Fe3+,U)(Nb,Ta)O
4.[4]
Samarskite crystallizes in the orthorhombic – dipyramidal class as black to yellowish brown stubby prisms although it is typically found as anhedral masses. Specimens with a high uranium content are typically metamict and appear coated with a yellow brown earthy rind.
Samarskite occurs in rare earth bearing granite pegmatites with other rare minerals. It occurs in association with columbite, zircon, monazite, uraninite, aeschynite, magnetite, albite, topaz, beryl, garnet, muscovite and biotite.[4]
Samarskite was first described in 1847 for an occurrence in Miass, Ilmen Mountains, Southern Ural Mountains of Russia.[3] The chemical element samarium was first isolated from a specimen of samarskite in 1879. Samarium was named after samarskite which was named for the Russian mine official, Colonel Vasili Samarsky-Bykhovets (1803–1870).[3]
Samarskite-(Yb) was first described in 2004 for an occurrence in the South Platte Pegmatite District, مقاطعة جفرسون، كولورادو.[6][7]
انظر أيضاً
- Decipium, a mis-identified new element, thought to have been extracted from samarskite in 1878 by Marc Delafontaine.
- قائمة المعادن
- قائمة المعادن المسماة على أسماء أشخاص
المراجع
- ^ https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Samarskite-%28Y%29 Archived 2019-08-11 at the Wayback Machine Mineralienatlas
- ^ أ ب "Mindat Samarskite-(Y)". Archived from the original on 2006-09-08. Retrieved 2006-08-20.
- ^ أ ب ت http://webmineral.com/data/Samarskite-(Y).shtml Archived 2011-05-14 at the Wayback Machine Webminerals
- ^ أ ب ت "Handbook of Mineralogy" (PDF). Archived (PDF) from the original on 2006-09-12. Retrieved 2006-08-20.
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ أ ب "Mindat Samarskite-(Yb)". Archived from the original on 2010-12-23. Retrieved 2011-02-22.
- ^ "Samarskite-(Yb) on Webmineral". Archived from the original on 2011-06-29. Retrieved 2011-02-22.