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24 published sheets
Sheet	Name	Formula	Mohs
ST-001 Igneous	Granite花岗岩 Granite is the rock most people name correctly and describe least accurately. It is the coarse, light-toned intrusive rock built from quartz, alkali feldspar and a little mica — but the iden Hand specimen	Quartz SiO₂ + alkali feldspar (KAlSi₃O₈) + plagioclase + mica	6–7 aggregate (quartz-controlled)
ST-002 Igneous	Granodiorite花岗闪长岩 Granodiorite looks like a slightly dirty granite and is routinely filed as one. It is the most abundant plutonic rock in the continental crust, and the difference from true granite is not co Hand specimen	Quartz SiO₂ + plagioclase (NaAlSi₃O₈–CaAl₂Si₂O₈) + hornblende + biotite	6–7 aggregate
ST-003 Igneous	Basalt玄武岩 Basalt is the most common rock on the planet's surface and one of the hardest to describe from a single specimen, because almost everything diagnostic is too small to see. It is dark, fine-g Hand specimen	Plagioclase (Ca-rich) + clinopyroxene + olivine; SiO₂ about 45–52 wt%	5–6 aggregate (pyroxene-controlled)
ST-004 Igneous	Obsidian黑曜岩 Obsidian is the geological exception that proves the rule about igneous rocks: it is an igneous rock that contains no minerals in the strict sense, because it cooled so fast that its atoms n Hand specimen	Amorphous SiO₂-rich glass, roughly 70–77 wt% SiO₂, with 1–3 wt% water	5–5.5 (glass hardness)
ST-005 Igneous	Pumice浮岩 Pumice is the only common rock that reliably floats on water, and the reason is simple arithmetic: 60 to 85 percent of its volume is gas. It is a volcanic glass foam, quenched so violently b Hand specimen	Amorphous SiO₂-rich glass with 60–85 vol% vesicles; SiO₂ about 65–75 wt%	6 (glass, but collapses under point load)
ST-006 Igneous	Gabbro辉长岩 Gabbro is what basalt becomes when it is given time. Identical in chemistry, it is the coarse-grained plutonic equivalent of the ocean floor's most common rock — and it is best known not for Hand specimen	Ca-rich plagioclase + clinopyroxene + olivine; SiO₂ about 45–52 wt%	6–7 aggregate
ST-007 Igneous	Granite vs granodiorite花岗岩与花岗闪长岩对照 These two rocks sit next to each other in every classification chart and are routinely confused in the field, because they share their texture, their grain size, most of their minerals and t Comparison sheet	Difference is in the feldspar budget: alkali feldspar-dominant versus plagioclase-dominant	Both 6–7 aggregate; hardness does not separate them
ST-008 Sedimentary	Sandstone砂岩 Sandstone is a photograph of a current. Every grain in it was moved by water or wind, and three measurements taken in the field — grain size, sorting and roundness — tell you how far it trav Hand specimen	Quartz grains (SiO₂) with a cement of silica, calcite, iron oxide or clay	6–7 for quartz grains; the rock's resistance is set by the cement
ST-009 Sedimentary	Limestone石灰岩 Limestone is the easiest of the common rocks to identify and the hardest to identify well, because one drop of acid answers the first question and leaves every interesting question untouched Hand specimen	CaCO₃, mostly as calcite, with variable clay, silica and magnesium	3 (calcite controls everything)
ST-010 Sedimentary	Shale页岩 Shale accounts for more than half of all sedimentary rock in the record and gets almost none of the attention. It is a mudrock — clay minerals, fine silt and often a few percent of organic c Hand specimen	Clay minerals + quartz silt + organic carbon; illite and kaolinite dominate	2–3 (clay minerals; the rock is soft and scratches with a fingernail in places)
ST-011 Sedimentary	Chert燧石 Chert is a sedimentary rock made of quartz so fine that no individual crystal can be seen at any useful magnification, and that fineness gives it two properties that changed human history: i Hand specimen	SiO₂ as microcrystalline quartz and chalcedony, with minor opal	7 (quartz hardness throughout)
ST-012 Sedimentary	Dolomite (dolostone)白云岩 Dolostone looks like limestone, breaks like limestone and is used like limestone, but a drop of acid gives it away — or rather, fails to. Its mineral, dolomite, is calcium magnesium carbonat Hand specimen	CaMg(CO₃)₂ — strictly the mineral is dolomite, the rock is dolostone	3.5–4 (slightly harder than calcite)
ST-013 Sedimentary	Bituminous coal烟煤 Coal is the one common rock that is biological rather than mineral in origin. It is the compacted and chemically altered remains of plants that grew in swamp forests and were buried before t Hand specimen	Variable: carbon 60–80 wt%, plus hydrogen, oxygen, nitrogen, sulphur and mineral ash	2–2.5; vitrain bands are harder, durain duller and tougher
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
ST-017 Metamorphic	Schist片岩 Schist is the middle grade of regional metamorphism — hot enough, roughly 400 to 600 degrees Celsius, for mica to grow into flakes you can see and for new minerals to crystallise that carry Hand specimen	Variable: muscovite, biotite, chlorite, quartz, feldspar, garnet, staurolite, kyanite	Variable with mineralogy; 4–7 depending on quartz and garnet content
ST-018 Metamorphic	Gneiss片麻岩 Gneiss is the highest grade of common metamorphic rock, formed at temperatures above about 600 degrees Celsius and often at pressures corresponding to 20 to 30 kilometres of burial. Its defi Hand specimen	Quartz + feldspar + biotite or hornblende, segregated into light and dark bands	6–7 (dominated by quartz and feldspar)
ST-019 Metamorphic	Quartzite石英岩 Quartzite is what happens to a pure quartz sandstone when it is buried deeply enough that the grains recrystallise and weld together. The cement disappears, the grain boundaries heal, and th Hand specimen	SiO₂, recrystallised from a quartz sandstone protolith	7 (quartz hardness throughout)
ST-021 Minerals	Quartz石英 Quartz is the most useful single mineral in field identification, not because it is interesting to look at but because of what its hardness does to everything else. At 7 on Mohs' scale it si Mineral species	SiO₂	7
ST-022 Minerals	Orthoclase (alkali feldspar)正长石（碱性长石） Orthoclase is the alkali feldspar — potassium aluminium silicate — and it is the mineral responsible for the pink colour of most granite. Its name means "right-angle fracture", referring to Mineral species	KAlSi₃O₈	6
ST-023 Minerals	Calcite方解石 Calcite is the reference mineral for hardness 3, the fizz in an acid test, and above all for cleavage — three perfect directions that break a crystal into rhombs and make calcite one of the Mineral species	CaCO₃	3
ST-024 Minerals	Pyrite黄铁矿 Pyrite is the mineral that built the phrase "fool's gold", and the deception works because pyrite genuinely looks metallic and golden in a stream bed. It is iron disulfide, the most common s Mineral species	FeS₂	6–6.5
ST-025 Minerals	Halite (rock salt)石盐（岩盐） Halite is sodium chloride — table salt — and it is the one common mineral for which taste is a legitimate field test. It forms by evaporation, it cleaves into perfect cubes, and it is soft e Mineral species	NaCl	2–2.5
ST-026 Minerals	Galena方铅矿 Galena is the main ore of lead, and it is one of the few minerals that announces itself by weight before you have looked at it properly. Pick it up and the density is startling — 7.6 grams p Mineral species	PbS	2.5–2.75

Igneous Sedimentary Metamorphic Minerals The field kit