What is Samarskite-(Y)?
Samarskite-(Y) is a dense black rare-earth niobate-tantalate from evolved pegmatites, valued for complex chemistry, radioactivity and collector locality information.
Mineralogy and crystal structure
Reference formula: (Y,Fe,U)(Nb,Ta)O4. Samarskite-(Y) is chemically variable and commonly metamict or radiation-damaged. No exact public COD model was selected for this batch, so the guide intentionally avoids a misleading artificial lattice. Samarskite-(Y) is classified with oxides and has a monoclinic crystal system. Typical hardness is 5–6 on the Mohs scale and specific gravity is approximately 4.3–5.8.
Colour, lustre and habit
Typical colours include black, brown-black, brown, grey. The usual massive, granular, prismatic habit and sub-metallic, resinous, dull lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Samarskite-(Y) forms in or is associated with rare-element granitic pegmatites and highly evolved alkaline rocks. Important documented localities include Russia, Norway, Sweden, Madagascar, Brazil, Canada and the United States.
A dense pegmatite mineral with a complex signature
Samarskite-(Y) is collected for the story contained in its chemistry: rare earths, niobium, tantalum and uranium mark an extremely evolved pegmatite. Documentation is more important than decorative polish.
Collecting and care
Store labelled and enclosed, limit handling and avoid dust. Do not cut, grind or heat; follow responsible practices for radioactive mineral specimens.
