Many famous "rubies" are in fact spinels, which look like rubies but are far less valuable. Spinels consist primarily of MgAl2O4, whereas rubies are primarily Al2O3. If the Timur Ruby, a 361-carat spinel, were pure MgAl2O4, how many moles of MgAl2O4 would it contain? (There are exactly 5 carats per gram.)