a mineral that contains carbon, oxygen, and the metallic element magnesium would be classified as ?
In response to Georock guy, magnesite would be an oxide (I think?) and dolomite is a carbonate.
Magnesite or dolomite. EDIT - In response to Katie, both magnesite and dolomite are carbonates, NOT oxides. Magnesite is MgCO3, so it is a compound containing exactly the elements C, O, and Mg. Dolomite is CaMgCO3. It is much more common than magnesite, but it still satisfies your criteria.
