| The most important cuprous compound is the oxide, which occurs in nature as ruby copper or cuprite. |
| Common red pigments include the minerals iron oxide, cadmium, and cuprous oxide and various synthetic organic pigments. |
| A reducing sugar, like lactose, is one which will chemically reduce the blue cupric ions of Benedict's solution to cuprous ions. |
| These reactions depend on the ability of the reducing sugar to convert cupric sulfate to cuprous oxide with a resulting color change. |
| Also, molten copper exposed to atmospheric oxygen contains embrittling cuprous oxide. |
| The blood-red substance consists chiefly of cuprous oxide with an admixture of tin oxide. |
