Tennant discovered Osnium in 1803 from samples of South American platinum.
[['S. Tennant', 'OBSERVED_OR_PREDICTED', '1803'], ['Osmium', 'NOTES', 'Tennant had been working on samples of South American platinum in parallel with Wollaston and discovered two new elements, which he named osmium and iridium.'], ['Osmium', 'OBSERVER', 'S. Tennant']]