Ruby / Corundum:
Malachite is a copper carbonate hydroxide mineral. Malachite often results from weathering of copper ores and is often found together with azurite, goethite, and calcite. Except for its vibrant green color, the properties of malachite are similar to those of azurite and aggregates of the two minerals occur frequently.
Ruby / Corundum is a crystalline form of aluminum oxide (Al2O3) typically containing traces of iron, titanium, vanadium and chromium. It is one of the naturally transparent materials, but can have different colors when impurities are present. Transparent specimens are used as gems, ruby if red and padparadscha if pink-orange. All other colors are called sapphire, e.g., "green sapphire" for a green specimen. Because of corundum's hardness (pure corundum is defined to have 9.0 Mohs), it can scratch almost every other mineral.