Vicky Veritas<p>Oh, Schist!</p><p>Schist is a metamorphic rock, whose name is one of those groan-worthy geology puns. Depending on how much mica is in the rock, schist can also be a remarkably strong, or it can be a little flaky:) Now for the fun stuff.</p><p>Schists are medium to high-grade (metamorphic pressure and temperature) medium-grained metamorphic rocks whose minerals are aligned in a preferred orientation perpendicular to the direction of the compressive forces that formed them, such as mountain building. Their foliation usually defines planes of weakness, but the strength of the rock can vary. Schists can form from sedimentary, igneous, and even other metamorphic rocks, but the composition of the original rock (protolith) must allow platy minerals to grow. Schists commonly contain quartz, feldspar, mica, chlorite, graphite, talc, and a variety of other minerals. Schists can also contain large well-formed crystals such as garnet (a metamorphic index mineral), emerald, sapphire, and ruby. If the protolith is known, the schist is named accordingly (ie meta-sandstone schist). If the protolith is unknown, the schist is named after its minerals such as mica-garnet schist, or greenstone, after its color, for a chlorite-bearing schist.</p><p>Schists are some of my favorite rocks. They can sparkle (thank you, mica) and are always fascinating rocks that indicate tectonics were involved in their formation. I never take them for granite:) I’ll show myself out…</p><p><a href="https://c.im/tags/schist" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>schist</span></a> <a href="https://c.im/tags/MetamorphicRock" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>MetamorphicRock</span></a> <a href="https://c.im/tags/geology" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>geology</span></a> <a href="https://c.im/tags/ScienceMastodon" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>ScienceMastodon</span></a></p>