Mineralogy · petrology · thin sections
Name the mineral. Read it in the hand, then under crossed polars — the way the exam actually asks.
Every rock is a set of minerals, and every mineral gives itself away — by how it looks in the hand, how it lights up under the microscope, and the atoms stacked inside it. This drills all three: hand specimen, thin section, and formula & structure — igneous and metamorphic — built from the real ID tables.
You're handed a specimen. Its properties come out one test at a time — the fewer you need before you name it, the more it's worth. Reveal what you must, then call it.
Name the mineral
The microscope stage. Some rounds hand you a mineral's optical properties in plane- and cross-polarised light; others show you a whole thin section to classify as a rock. Read the light.
What is it?
The atoms behind the properties. Match a mineral to its chemical formula, or to the silicate structure that decides how it breaks — the reason mica peels and quartz shatters.
Pick the match
The reference bench — the Mohs scale, the silicate structures that control cleavage, the optical vocabulary, and the full ID table.
With the common field testers you actually have on hand.
As you polymerise the SiO₄ tetrahedra from isolated to framework, the cleavage changes — this is the "why" behind the breaks.
As grade climbs, these appear in order. Whichever one you see tells you how hot it got.
Every mineral in the game, with its diagnostic properties.