Obsidian Igneous A natural volcanic glass formed in quick-cooling lava. Sharp edged but smooth on surface. Colours: black, purple blue Elements: Silicon (Si) oxygen (O) Rarity: Uncommon 6.5 Moh scale rating Granite Igneous A rough, sandy rock created by slowly cooling lava. Speckled texture Colours: Range from white to grey Rarity: Common 7.0 Sandstone Sedimentary 6.5/7 Made of small sand pieces including Quartz, feldspar and other mineral fragments. Found mainly underwater but also in deserts. Colours: red, orange , brown white Rarity: Common Elements: Si O K Na Coal Sedimentary 3.5 Formed by the fossilized remains of a plant. Found in bogs and swamps. Useful for steam power and heating. Charcoal is a quicker version made by burning wood and timber. Colours: Black Elements: C H O (S N) Quartzite Metamorphic 7.0 Made mainly of Quartz, a metamorphosed version of Quartz sandstone. Often white like the sand which it was made from. Has a medium grainy texture. Colours: White, brown or green. Rarity: Rare. Diamond Gemstone Hardest thing known to man. Usually found clear but can be most colours of the rainbow. Made from carbon. Used in jewellery and saws. The colours in the diamond depend on the impurities of it. For example boron makes it a blue and nitrogen makes it yellow. Colours: Mainly white can be any other colour. 10 Elements: C(can contain small amounts of B & N). Rarity: Extra-extremely extraordinarily rare!!!!!