platiniridium
/ˌplatɪnɪˈrɪdɪəm/Mineralogy and Metallurgy
noun
An alloy of platinum and iridium, especially when occurring naturally, typically as white rounded or angular grains.
Origin
Mid 19th century; earliest use found in James Dana (1813–1895), geologist, zoologist, and teacher. From platin- + iridium.