Stonetable — a field notebook for rocks and minerals
Thirty specimen sheets, four groups, every one built around the tests you can actually run on the outcrop: hardness, cleavage, streak, acid, magnetism, density. Written in English and Chinese. Released a few sheets at a time rather than all at once.
火成岩IgneousCooling history written in grain size: coarse where the melt ponded underground, glassy where it was chilled at the surface.3 sheets live
沉积岩SedimentaryGrains, cements and bedding. These are the rocks that record water, wind, life and time without metamorphosing any of it away.2 sheets live
变质岩MetamorphicThe same protolith at different grades: shale becomes slate, then phyllite, then schist, then gneiss, and each step is readable.2 sheets live
矿物MineralsIdentified by properties rather than names: hardness, cleavage, streak, lustre, acid reaction, magnetism, density.3 sheets liveIgneous rocks — solidified from melt
| 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-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-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 |
Sedimentary rocks — deposited, then lithified
| Sheet | Name | Formula | Mohs | |
|---|---|---|---|---|
| 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) |
Metamorphic rocks — recrystallised under pressure and heat
| 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 |
Minerals — the single substances rocks are made of
| Sheet | Name | Formula | Mohs | |
|---|---|---|---|---|
| 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-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 |
How to use the index
The index is a log table, not a catalogue of names. Read down the hardness column first: if your specimen is scratched by a knife, you are looking in the upper part of the list; if it scratches glass, you are in the lower part. Two or three sheets will then cover the whole plausible range, and the field tests at the top of each sheet will separate them.
- Start with the group your specimen most resembles, not with the name you hope it is.
- Run the tests in the order given on the sheet. They are ordered so that the cheapest and most decisive test comes first.
- Record the number, not the adjective. Write 6, not hard. Write greenish-black, not dark.
- If two sheets both seem to fit, go to the comparison sheet where one exists — the four comparison sheets in this collection cover the pairs that are most often confused.
What each sheet contains
A specimen plate, a properties table, an ordered list of field tests with the result each should give, the narrative sections, representative localities with coordinates, the minerals or rocks most often confused with it and how to separate them, storage and handling notes, and the key points in five lines. Sheets are published on a schedule; anything not yet live is absent from the index, the search box and the site map.
- Properties: hardness on Mohs' scale, streak, lustre, cleavage, fracture, colour, crystal system, habit and grain index.
- Field tests: four tests per sheet, each with the exact expected result, not a range.
- Locality: three representative places with coordinates and a note on what occurs there.
- Handling: the hazards that actually matter — lead, sulfide dust, acid, deliquescence, cave protection.
A word on the plates
Each sheet is illustrated with a generated wireframe rather than a photograph, because a schematic can carry the diagnostic information and a photograph cannot. Crystal forms are projected polyhedra; line weight is scaled to the mineral's hardness, dashed traces mark cleavage directions, and a seam marks characteristic twinning. Rocks, which have no crystal form, are drawn as fabric plates showing the texture that identifies them: grain mosaic, bedding laminae, vesicles, or conchoidal fracture.
Publication schedule
- 10 sheets are live. A further 20 are written and scheduled, and go live on their dates.
- Unpublished sheets are absent from the index, the search box, the category pages and the sitemap, and their URLs return 404 until they go live.
- The index tables and category counts always equal what is actually live; nothing is listed that cannot be opened.