I've just had a quick search, and apparently both seussite and greigite are named after people, exactly like davemaoite.
> Suessite is a rare iron silicide mineral with chemical formula: Fe₃Si. The mineral was named after Professor Hans E. Suess.
And:
> Greigite is an iron sulfide mineral with the chemical formula Fe2+ Fe3+ 2S 4. It is the sulfur equivalent of the iron oxide magnetite. [and was] named after the mineralogist and physical chemist Joseph W. Greig.
> Suessite is a rare iron silicide mineral with chemical formula: Fe₃Si. The mineral was named after Professor Hans E. Suess.
And:
> Greigite is an iron sulfide mineral with the chemical formula Fe2+ Fe3+ 2S 4. It is the sulfur equivalent of the iron oxide magnetite. [and was] named after the mineralogist and physical chemist Joseph W. Greig.
(From Wikipedia)