Metamorphic rocks form when a preexisting rock (protolith) is transformed into a different rock due to pressure, heat, or chemical alteration. Tectonics and burial can supply pressure and heat on a wide scale (regional metamorphism), while igneous intrusions can bake adjacent rocks (contact metamorphism). Hydrothermal fluids power chemical alteration. This page has useful diagrams of metamorphic processes, while this one has good notes, and this one has both! Read more
Metamorphic rocks, minerals, grade, and facies
Cortney Science & Technology + geology, metamorphism, minerals, rocks
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Most common elements and oxides in rock-forming minerals
Cortney Science & Technology + geology, minerals, oxides, rocks
After the Big Bang, the universe was made up of the two lightest elements: hydrogen and some helium. Nucleosynthesis was responsible for creating heavier elements; young stars form helium out of hydrogen.
In the later stages of a massive star's life, helium is converted into heavier elements like carbon, oxygen, silicon, and iron. When a star goes supernova, they create elements heavier than iron. Elements with even atomic numbers are an order of magnitude more common than odd ones. Read more →
Best trick for learning the seven crystal systems
Cortney Education, Science & Technology + crystals, earth science, geology, minerals
You can find various websites discussing the crystal systems (see my short list below), but in all honesty, the best way to mastering these systems is to deal with them in 3D. Read more →
12 great intro to optical mineralogy resources [updated]
Cortney Education, Science & Technology + earth science, geology, minerals, optical mineralogy, petrographic microscope
The following list contains the websites I visited most often when I studied optical mineralogy; these sites saved my butt on more than one occasion! A lot of the sites overlap in information, but sometimes a particular site had that key picture or explanation that was essential for me in understanding a concept. I've organized the sites into two groups depending on whether they focus on explaining mineralogy properties or identifying specific minerals. (Image from Geoffrey Clarke.)