Sixty samples of samarskite were collected from a mica pegmatite vein in Nellore district, S. India.
The physical and chemical properties of six representative samples from this collection were studied.
Numbers 1 and 6 of the selected samples of samarskite were intergrown with Columbite-Tantalite.
The specific gravity of these six specimens varies from 5·567 to 5·776. The hardness is between 5 and 6. The colour varies from dark steel grey to velvet-black and the streak is generally brown to dark-brown. They all break with conchoidal fracture.
Specimen No. 1 which is an intergrowth of samarskite with Columbite-Tantalite was polished and placed in contact with a panchromatic photographic plate. Only the samarskite portion affected the photographic plate.
The chemical analysis of samarskite shows a variation in UO3 percentage from 4·2 to 10·5% and the Nb2O5+Ta2O5 from 53·4 to 69·7%. Attention is drawn to the fact that the UO3 percentages of samarskite from the Nellore area differ from those of North Carolina.