As nouns the difference between martite and marmite

is that martite is (geology|mineralogy) a variety of hematite that is pseudomorphic after magnetite crystals while marmite is something which people either love or hate.

As a proper noun marmite is

(australia|british|new zealand) a sticky, dark brown, strongly flavoured spread based on a yeast extract (a by-product of beer brewing), eaten on toast, in sandwiches, etc.

As a verb marmite is

to apply marmite to.