Millstone Grit	Sandstone	Slate
coarse sandstone,was used to make millstones for grinding corn and grindstones.	formed from beach, river or desert sands, can be white, pink, red, yellow or brown,	formed from shale, can be black, grey, red or green, breaks into thin sheets,
	some used for building stones and flagstones, and in making glass, is permeable and porous.	is soft, can be cut easily, but is strong and hardwearing, used for roofs, steps and table tops, sometimes for small blackboards.
Limestone		Chalk
hard, contains lots of shells, can be white, grey, brown or yellow, dissolves quickly, forms stalactites and stalagmites in caves, used for building stones and roads.		soft, white, porous, contains remains of small animals and shells and lumps of flint, used to make sticks of chalk.
Flint		Granite
a type of quartz, can be black, grey or dark brown, used by early man for axes and arrow heads.		hard,coarse particles, can be white, grey, pink or red, is strong,
		used for buildings, steps and monuments.
Quartz		Pumice
found as crystals in other rocks, has a glassy, greasy or waxy look, can be transparent or any colour, purple quartz is called amethyst, blue is sapphire, grey, black or dark brown is flint, used by builders in concrete, plaster and glass.		a kind of lava, full of gas bubbles, light enough to float, can be white, grey or yellow, used in making concrete, rubbing down metal or wood and sculptures.
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