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.Know More
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.Learn more about Geology
Conglomerate rocks are formed by the sedimentary rock process, which is: erosion, transport, deposition and cementation. Two characteristic properties of conglomerate rock are that the sedimentary particles, or clasts, are greater than 2 millimeters in size, and the clasts are rounded in appearance. Sedimentary rocks with angular clasts are distinguished from conglomerates and are called breccias.Full Answer >
When water combines with melted rocks in the magma chamber of the volcano, it pushes magma upward. Gas molecules form bubbles that expand as they rise. The pressure from the bubbles becomes stronger than the surface rock and it fractures, allowing the magma to reach the surface.Full Answer >
As of August 2014, the oldest sedimentary rocks known are banded iron formations from Greenland and Quebec that have been dated to 3.8 or 3.9 billion years old. The material composing these rocks may have been extracted from the Earth's mantle as much as 4.28 billion years ago.Full Answer >
Graphite is normally found in the form of flakes in metamorphosed rocks. The rocks in which graphite is found are rich sources of carbon and other carbon-containing compounds. Graphite is a carbon allotrope and is also obtained from veins and in pegmatites.Full Answer >