Accumath Toolchest — Minerals Dataset: Notes

Dataset file: accumath-minerals.csv Built: 2026-10-20 Rows: 131 minerals × 13 columns

Sources and method

Every row was gathered from an individual mineral data page that was opened and read — no values from memory, nothing estimated. The source column names the source per row:

Source	Rows
The Mineralogy Database — webmineral.com	98
Mindat — mindat.org	33

Values are published facts recorded with attribution; no descriptive text was copied. Working fragments are preserved in ~/workspace/your_files/.minerals-frag/ (batchA–batchF.json) for provenance.

Recording conventions (applied across all batches):

Specific gravity = the source page's measured Density range where webmineral was the source. Webmineral pages also print a single calculated "Specific Gravity of X =" figure; that number is a computed average, so it was not used — using it would have collapsed published ranges to a point, which this dataset never does.
Mohs hardness = the numeric value or range as printed (webmineral appends descriptive suffixes like "- Copper Penny"; only the number/range was recorded).
Ranges are recorded exactly as printed, including two webmineral quirks kept verbatim: ferberite and hubnerite SG ranges are printed in descending order ("7.5 - 7.4", "7.2 - 7.1"), and the cleavage planes for grossular and hornblende are literally printed as "{???}" on their pages — recorded as printed and flagged in-row rather than guessed.
Formulas exactly as printed, including webmineral's charge notation (e.g. siderite Fe++CO3), the turquoise formula as printed, and montmorillonite's comma-decimal formula as printed. Hydration water is preserved (e.g. gypsum CaSO4·2H2O).
Crystal system = the system name (class suffixes such as "- Hexagonal Scalenohedral" dropped).

Coverage by category

Category	Rows
Silicate	59
Oxide	18
Sulfide	15
Carbonate	12
Native element	6
Sulfate	5
Halide	4
Phosphate	4
Borate	3
Tungstate	3
Hydroxide	2

Classification note: quartz, chalcedony, and opal are counted as oxide following their Strunz class (04.DA), which is how webmineral classifies them; the Dana system treats them as tectosilicates. This dual classification is noted in their rows.

The Mohs scale (reference)

The canonical ten-mineral scale, with the standard sclerometer (absolute hardness) comparison as commonly tabulated (Wikipedia, "Mohs scale of hardness", retrieved 2026-10-20):

Mohs	Mineral	Formula	Absolute hardness (sclerometer, relative)
1	Talc	Mg3Si4O10(OH)2	1
2	Gypsum	CaSO4·2H2O	2
3	Calcite	CaCO3	14
4	Fluorite	CaF2	21
5	Apatite	Ca5(PO4)3(OH,Cl,F)	48
6	Orthoclase	KAlSi3O8	72
7	Quartz	SiO2	100
8	Topaz	Al2SiO4(OH,F)2	200
9	Corundum	Al2O3	400
10	Diamond	C	1500

The steps are not equal. The Mohs scale is ordinal — it ranks scratch resistance only. In absolute terms corundum (9) is about twice as hard as topaz (8), but diamond (10) is about four times as hard as corundum — the 9→10 step is far larger than any other step on the scale. All ten reference minerals are rows in this dataset (apatite is represented by its fluorapatite row).

Groups, series, and naming — how they are handled

Plagioclase series: albite, oligoclase, labradorite, anorthite are separate rows (the series members webmineral carries data pages for); each notes the series and its Ab/An position.
Olivine group: represented by its end-members forsterite (Mg) and fayalite (Fe).
Garnet group: almandine, pyrope, grossular.
Tourmaline group: schorl and elbaite.
Wolframite series: ferberite and hubnerite (webmineral's Dana class for both literally reads "Wolframite series").
Apatite group: the row is fluorapatite (webmineral titles its page "Apatite-(CaF)" — flagged in the row).
Zeolite group: analcime, natrolite, laumontite, and the Ca-dominant series members heulandite-Ca, stilbite-Ca, chabazite-Ca (the rows keep the familiar names; the series-member formulas are what is printed in them, with the fact stated in-row).
Serpentine group: antigorite. Chlorite group: clinochlore. Apophyllite group: fluorapophyllite-(K), named as its source page titles it.
Hornblende is a group name, not a single species; webmineral's Hornblende page resolves to its magnesiohornblende data table, and the row records that data with the fact noted in-row. Biotite and illite are likewise group names as printed by the source.
Old/field names: "psilomelane" → the row is romanechite, the main mineral behind that discredited name (stated in-row). "Limonite" → the row is goethite, with the limonite note in-row. Titanite is also called sphene (in-row). Celestite's webmineral page is titled "Celestine" (in-row). Columbite-(Fe) was formerly "ferrocolumbite" (in-row).
Varieties are not separate rows: agate (banded), amethyst, citrine, rose quartz, smoky quartz, jasper, and chert/flint are quartz/chalcedony varieties — covered in the quartz row's notes.

Drops

Bauxite — dropped. No mineral data page exists for it on webmineral or on Mindat's mineral pages (only locality/rock pages). Bauxite is a rock — a mixture of aluminum hydroxide minerals — not a mineral species, so there was no verified property set to record. It is the only scope item dropped; every other mineral in the original scope was verified from an opened page.

Source disagreements (recorded value = the row's named source)

Plagioclase hardness: webmineral prints 7 for albite, oligoclase, and labradorite — higher than the 6–6.5 most other compilations list for plagioclase. Recorded as printed and flagged in each row. (Anorthite prints 6 on the same site.)
Hematite: webmineral hardness 6.5, SG 5.3, luster Metallic — vs Mindat hardness 5–6, SG 5.26, and a broader luster list. Webmineral recorded.
Pyrolusite: the row is Mindat (SG 5.04–5.08, hardness 2–6.5) because webmineral's full data page was not opened by the gatherer; a webmineral determinative table seen in search results lists SG 4.73 and hardness 6–6.5. Flagged for re-verification.
Enstatite / diopside / augite: webmineral's hardness and density ranges differ from the Handbook of Mineralogy's (widest gap: enstatite — webmineral hardness 5.5, density 3.1–3.3; Handbook hardness 5–6, measured density 3.2–3.9). Webmineral recorded.
Zircon and molybdenite: internal webmineral inconsistencies — the Density field and the same page's calculated-SG note disagree (zircon 4.6–4.7 vs 4.85; molybdenite 5.5 vs 5.00). The Density field was recorded in both cases, per the convention above.
Siderite hardness: webmineral prints a single 3.5; a Mindat snippet gives 3.5–4.5. Webmineral recorded.
Spinel SG: webmineral 3.57–3.72 vs Mindat measured 3.6–4.1. Webmineral recorded.
Romanechite hardness: Mindat 5–6 vs 6–6.5 in other summaries. Mindat recorded (it is the row's source).
Chrysocolla streak: Mindat "Light green" (recorded) vs "White when pure" in the Handbook of Mineralogy.

Blank cells (unstated on the source page — left blank, never filled by inference)

chalcedony: crystal_system · romanechite: specific_gravity, cleavage, fracture · spodumene: streak, cleavage, fracture · fluorapophyllite-(K): streak · ulexite: streak · datolite: cleavage · uraninite: cleavage · illite: fracture.
Two Mindat rows (chalcedony, spodumene) were verified from Mindat content returned in search results because direct Mindat page opens returned HTTP 403 to the text fetcher during this build; their blank fields are the ones a full page read would most likely fill. (Other Mindat rows were read from fully opened pages.)

Spot check

The calcite row was re-verified cell-by-cell against its live webmineral page after the merge (formula CaCO3, trigonal, hardness 3, density 2.71, cleavage {1011} Perfect, luster Vitreous, streak white, fracture Conchoidal, colors as listed) — exact match.