Granite rock: Granites can be white, pink, or gray in color and with at least 20% quartz.
Obsidian: Forms when molten rock cools very rapidly. Also the texture of it is glassy. Obsidian is a naturally occurring volcanic glass formed as an igneous.
Pumice: light-colored, extremely porous igneous rock that forms during explosive volcanic eruptions. And the texture is rough.
Rhyolite: is an igneous rock, volcanic rock of felsic. And the texture is glassy also.
Slate: Most slates are gray in color and range in a continuum of shades from light to dark gray. Slate also occurs in shades of green, red, black, purple and brown. The color of slate is often determined by the amount and type of iron and organic material that are present in the rock.
Schist: If you look at a piece of this metamorphic rock you will be able to see crystals. Also the texture is foliated.
Gneiss: the colors of a gneiss rock can be a lite color or a dark color or just alternated dark colors. And the texture is rough.
Marble: you can identify a marble by its texture witch is smooth and glassy.
Quartzite: is a really hard rock and is composed mostly from sandstone. And the texture is granular.
Shale rock: is a secondary rock
Sandstone: is a clastic sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust.
Conglomerate: are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias.
limestone: is composed of skeletal fragments of marine organisms such as coral or foraminifera.
Travertine: formed by rapid chemical precipitation.