Rock Types
🔥 Igneous — cooled from magma/lava
🌊 Sedimentary — compressed layers
⚡ Metamorphic — heat & pressure transformed
Hardness Scale (Mohs)
1. Talc · 2. Gypsum · 3. Calcite
4. Fluorite · 5. Apatite · 6. Feldspar
7. Quartz · 8. Topaz · 9. Corundum · 10. Diamond
Quick Tests
• Streak — scratch on unglazed porcelain
• Acid — drop vinegar (fizzes = calcite)
• Magnet — test for magnetite
• Scratch — fingernail, coin, knife, glass