Unit 01 · Minerals
Minerals are the building blocks of every rock, so this is where the course begins. You start from the definition — a naturally occurring, inorganic, crystalline solid with a definite composition — then learn to identify unknown specimens the way a field geologist does: by streak, Mohs hardness, cleavage versus fracture, luster, crystal habit, density, and the dilute-acid fizz test for carbonates. Working a dichotomous key, you name quartz, feldspar, mica, calcite, pyrite, halite, gypsum, and hornblende. Mastery means you can run each physical-property test cleanly and explain why a property separates one mineral from another — and see how it all sits inside Hutton’s deep time, where these crystals are the slow record of Earth’s making.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| What a mineral is | Calls any solid a mineral; says a rock is a mineral. | Recites part of the definition but misses a requirement (e.g. forgets “inorganic” or “crystalline”). | States all four requirements — naturally occurring, inorganic, crystalline, definite composition — and explains that a rock is made of one or more minerals. |
| Streak & luster | Reads the specimen’s surface color as its streak; cannot name luster. | Gets a streak on the plate but forgets that streak can differ from surface color; luster call is inconsistent. | Powders the mineral on the porcelain plate to read true streak, and classifies luster as metallic or non-metallic to narrow the field — e.g. pyrite’s greenish-black streak under a brassy metallic shine. |
| Mohs hardness | Guesses hardness by appearance; misuses the kit. | Runs scratch tests but reverses which scratches which, or reports a single number instead of a range. | Uses fingernail, copper penny, glass plate, and steel nail methodically to bracket hardness on the Mohs scale and reads it accurately (e.g. calcite ~3, quartz 7). |
| Cleavage vs. fracture | Uses the terms interchangeably or not at all. | Defines both but misreads a specimen — calls conchoidal fracture “cleavage” or misses a plane. | Distinguishes flat cleavage planes from irregular fracture, counts cleavage directions, and cites mica’s one perfect cleavage against quartz’s fracture. |
| Special tests & the dichotomous key | Skips the acid test; cannot follow a key past the first branch. | Runs the dilute-acid fizz test but forgets what it confirms, or loses the thread partway through the key. | Applies the dilute-acid carbonate fizz test to confirm calcite, folds density and crystal habit into the call, and works a dichotomous key end-to-end to name an unknown specimen. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“It fizzed under the dilute acid, so it’s a carbonate — and the steel nail scratched it easily, hardness near 3, with a white streak and rhombic cleavage. That’s calcite. Hardness is what rules out quartz here: quartz would scratch the glass plate, calcite won’t. The key gets me to the name; the tests tell me why.”
“It’s kind of gold, so… pyrite? And it looks hard, I think — I didn’t really do the streak, the outside was already that color.”
You demonstrate this unit through the mineral-identification lab — streak, hardness, cleavage, luster, and the acid test on a specimen set — plus short oral checks where you reason from the properties aloud, all recorded in your lab notebook, not a multiple-choice test. A criterion counts as mastered only when you can both run the test with proper technique and justify why that property distinguishes one mineral from another. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.