Geology.com offers many pictures of rocks, divided into their fundamental categories of igneous, metamorphic and sedimentary. The igneous rock section divides the rocks into extrusive and intrusive types, with special sections for gabbro, peridotite, tuff and others. The metamorphic rocks are divided into foliated and non-foliated rocks, with 10 separate sections focusing on marble, schist, gneiss and other rocks.
Geology.com further divides sedimentary rocks into clastic, chemical and organic types, with a dozen sections devoted to conglomerate rocks, limestone, siltstone and more.
In addition, the site offers pictures of rocks and explanations of special phenomena regarding rocks such as the sliding rocks of racetrack playa. Further pictures are available of rocks on Mars, which appear to be very similiar to rocks on Earth. Another section offers pictures of lava, explaining and showing how a rock can be molten and liquid.
One gallery of pictures features types of sand from all over the world, with photos of exotic orange, green, black and white sands, among others. A separate photo gallery shows the beauty of individual grains of sand. Another close-up set of photos focuses on the beauty of coal when seen through a microscope.
One further startling photo gallery shows a rockfall at Yosemite National Park, along with the accompanying debris avalanche.