Slate can be described very simply as a sedimentary mud rock, compressed and compacted over time and altered by metamorphism (a combination of heat and pressure) to form a very hard rock with well defined cleavage lines. These cleavage lines enable the slate to be easily “split” or “cleft” which gives slate its’ characteristic appearance. Slates can vary in colour depending on the different minerals that were introduced during their metamorphosis. Bright colours such as greens, reds, yellows and purples can be found, as well as the more common greys and blacks. Slate is generally harder than other sedimentary rocks like Limestone and Sandstone and is available in a matt, eggshell finish as well as the better-known riven, cleft finish. Grey, black and green slates are very popular in the worktop and vanity top market where their consistent, matt appearance is much sought after.