Metamorphic rocks and minerals
The same protolith at different grades: shale becomes slate, then phyllite, then schist, then gneiss, and each step is readable.
| Sheet | Name | Formula | Mohs | |
|---|---|---|---|---|
| ST-015 Metamorphic | Marble大理岩 Marble is limestone that has been cooked. Given enough heat and pressure, calcite grains recrystallise into a dense interlocking mosaic, the fossils and bedding are destroyed, and the rock b Hand specimen | Recrystallised CaCO₃; dolomitic marble is CaMg(CO₃)₂ | 3–4 (calcite marble), 3.5–4 (dolomitic marble) | |
| ST-016 Metamorphic | Slate板岩 Slate is the grade of metamorphosed mud that industry was built on: it splits into thin waterproof sheets, which made it the roofing material of eighteenth- and nineteenth-century Europe and Hand specimen | Fine-grained white mica (sericite), chlorite and quartz after a shale protolith | 3–4; the rock is soft but splits into very tough sheets |
