1. Streak Test: This test involves rubbing the rock on a streak plate (a piece of unglazed porcelain). The color of the powder left behind is called the streak and can be a helpful identifier for certain minerals. For example, hematite will leave a reddish-brown streak, while pyrite will leave a black or greenish-black streak.
2. Hardness Test: This test involves scratching the rock with a series of known minerals or objects with a specific hardness. The Mohs Hardness Scale is a standard scale used for this test. By comparing the hardness of the unknown rock to the known minerals, you can get a good idea of what minerals are present. For example, if the rock scratches glass (hardness 5.5), you know it contains minerals harder than glass, like quartz or feldspar.
