""'Calliostoma problematicum " "'is a species of sea snail, a marine gastropod mollusk in the family Calliostomatidae.
2.
Nevertheless, he was not able to identify this metal and gave it the names " aurum paradoxium " ( paradoxical gold ) and " metallum problematicum " ( problem metal ), because it did not exhibit the properties predicted for antimony.
मोबाइल