Magnesite rhymes with:
anthracite, leukocyte, lymphocyte, parasite, phagocyte, plebiscite, andesite, anthracite, brucite, calcite, eyesight, felicite, foresight, granulocyte, gravesite, hindsight, hussite, insight, leukocyte, lucite, lymphocyte, oversight, parasite, phagocyte, plebiscite, procyte, starsight, website
Magnesite sounds like:
machinist, macknight, maximized, mcknight, mcnaught, mechanized, miscommunicate, mismanaged, misogynist