Know all about Oil shale and Variolite properties here. All properties of rocks are important as they define the type of rock and its application. Oil shale belongs to Sedimentary Rocks while Variolite belongs to Igneous Rocks.Texture of Oil shale is Splintery whereas that of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular. Oil shale appears Muddy and Variolite appears Dull and Soft. The luster of Oil shale is dull while that of Variolite is not available. Oil shale is available in black, brown, buff, green, grey, red, yellow colors whereas Variolite is available in black, brown, light to dark grey colors. The commercial uses of Oil shale are an oil and gas reservoir and that of Variolite are cemetery markers, creating artwork.