The Earth is home but we are often unfamiliar with it. Sandatlas is a fun website that describes the rocks around us. Created by an Estonian PhD student, it helps the user find descriptions and explanations of various igneous, sedimentary and metamorphic rocks. While the purpose of this site is educational, the images are beautiful and fascinating. Each section is followed by a bibliography.
Clicking on the link to study igneous rocks and minerals, the user finds an explanation that can be scanned for the interested novice or used by the more serious scholar to understand how they are classified as well as the evolution of the classification system. Large, detailed and brightly coloured images allow the user to see the rocks clearly, and the charts explain their chemical composition and rocks that do not readily fit into classification schemes (in this case, obsidian and diabase and scoria).
Sedimentary rocks include mudstone, sandstone and limestone. The composition of these can make for brilliant colouration – Bauxite with major impurities of iron oxides and hydroxides make it as orange as a pumpkin; the evaporate can be a different hue of coral; and sandstone can be in the rose to rust continuum. Travertine can take on mysterious patterns like marbleized paper. Metamorphic rocks are those that have been changed by elevated pressure and temperature. Eclogue is stunning, with green pyroxene omphalites and red garnet. Marble is metamorphic as well, recrystallized carbonate rock (limestone, dolomite rock).
Users can browse by type of rock, or use a list to navigate to specific rocks or topics such as conchoidal fractures, an explanation of what sand is and how it is formed, explanations of why there are “u” and “v” shaped valleys, and classification of sand (very fine to gravel, based on the number of grains in one centimeter cubed) and volcanic gases, to name a few.
Users can leave their thoughts on a comment feature, so the experts can share their knowledge about these rocks. Students and scholars will appreciate this website for the content, and those of us who simply want to revel in the beauty of rocks will appreciate it as well.
