Answer
The common ores of magnesium are:
Dolomite ($CaMg(CO_{3})_{2}$), Magnesite ($MgCO_{3}$), Brucite ($Mg(OH)_{2}$), Carnallite ($KMgCl_{3}·6(H_{2}O)$), Talc ($Mg_{3}Si_{4}O_{10}(OH)_{2}), Epsomite ($MgSO_{4}·7H_{2}O) and Olivine ($(Mg, Fe)_{2}SiO_{4}$).
The common ores of calcium are: Calcite ($CaCO_{3}$), Dolomite ($CaMg(CO_{3})_{2}$), Gypsum ($CaSO_{4}·2H_{2}O$), Fluorite ($CaF_{2}$), Bentonite etc.
Work Step by Step
The common ores of magnesium are:
Dolomite ($CaMg(CO_{3})_{2}$), Magnesite ($MgCO_{3}$), Brucite ($Mg(OH)_{2}$), Carnallite ($KMgCl_{3}·6(H_{2}O)$), Talc ($Mg_{3}Si_{4}O_{10}(OH)_{2}), Epsomite ($MgSO_{4}·7H_{2}O) and Olivine ($(Mg, Fe)_{2}SiO_{4}$).
The common ores of calcium are: Calcite ($CaCO_{3}$), Dolomite ($CaMg(CO_{3})_{2}$), Gypsum ($CaSO_{4}·2H_{2}O$), Fluorite ($CaF_{2}$), and Bentonite.