Rock, Mineral & Geology Guides

Browse every free guide and tool

• Identify from specimen photos — Upload rock, mineral, or fossil photos for an evidence-led shortlist, safety notes, and confirmation steps.
• Quick ID by properties — Narrow an unknown without a photo or account using observable physical properties.
• How to identify rocks and minerals — Follow a safety-first workflow from context and texture to a defensible candidate shortlist.
• Printable rock and mineral ID chart — Compare rock textures, mineral properties, common examples, and safer next tests.
• Mineral identification chart — Search, filter, and print 21 common minerals by hardness, lustre, streak, cleavage, and diagnostic clues.
• Mohs hardness scale and test tool — Use the ten-mineral scale, safer scratch instructions, and a private range estimator.
• Mineral streak test colour chart — Interpret an existing streak with a printable chart, private colour lookup, and safer testing limits.
• Mineral cleavage vs fracture chart — Compare cleavage directions, angles, fragment shapes, and fracture types with a private lookup.
• Mineral luster and lustre chart — Compare metallic, glassy, pearly, silky, resinous, waxy, dull, and earthy surfaces.
• Mineral color and colour chart — Compare common and variable colours while avoiding colour-only identifications.
• Mineral magnetism test chart — Compare strong, weak, localized, and absent magnetic responses with safer test limits.
• Mineral transparency chart — Separate transparent, translucent, and opaque observations while accounting for thickness and inclusions.
• Mineral crystal habit chart — Compare common single-crystal and aggregate shapes without confusing habit, system, cleavage, or cut facets.
• Crystal identification chart — Build a broad crystal or mineral shortlist from lustre, hardness, cleavage, habit, streak, context, and gem-authentication limits.
• Geode identification guide — Separate geodes from agate nodules, concretions, thundereggs, amygdules, vugs, and slag.
• Meteorite identification guide — Screen a possible meteorite against slag, magnetite, hematite, vesicular rock, and manufactured metal without claiming confirmation.
• Mineral fluorescence chart — Compare long-wave and short-wave UV responses, phosphorescence, common fluorescent minerals, and safety limits.
• Rockhounding for beginners — Plan a first trip with a private checklist for permission, collecting rules, hazards, field gear, stewardship, and specimen ID.
• Ontario rock identification guide — Compare Shield, sedimentary, beach, glacial, and mining-area finds with a private helper and official Ontario map sources.
• Rock tumbling for beginners — Screen rough by identity, durability, structure, and compatibility while controlling abrasive stages, slurry, and silica.
• Rock and mineral specimen label maker — Create private field tags, catalog labels, and display labels with locality controls and local CSV export.
• Rock and mineral collection inventory — Catalogue personal specimens locally, search records, and export CSV or restorable JSON backups.
• Geologic time scale chart — Look up an age, compare current ICS eons, eras, periods, and Cenozoic epochs, and print the chart.
• Free geology calculators and earth science tools — Browse 37 private calculators organized by field, mapping, mining, drilling, groundwater, material, sediment, and earth-system tasks.
• Strike and dip calculator — Convert right-hand-rule strike and dip, draw the plane, and calculate apparent dip for a cross-section.
• Stereonet plotter — Plot up to 250 RHR planes and poles on a private lower-hemisphere equal-area net.
• Sediment grain size and phi calculator — Convert millimetres, micrometres, and phi and locate a particle on the detailed Udden–Wentworth scale.
• USDA soil texture triangle calculator — Enter sand, silt, and clay percentages, find one of 12 USDA texture classes, and plot the composition.
• Atterberg limits and plasticity index calculator — Calculate PI, optional liquidity and consistency indices, and a conservative USCS plasticity-chart position.
• Soil dry density and relative compaction calculator — Convert moist density to dry density and compare it with an entered laboratory maximum and explicit project target.
• Sieve analysis and grain size distribution calculator — Plot percent-passing or mass-retained data and calculate bounded D10, D30, D60, Cu, and Cc.
• USCS soil classification calculator — Assign a transparent inorganic group symbol from sieve fractions, Atterberg limits, and bounded D-values.
• Core recovery and RQD calculator — Calculate recovery and rock quality designation for one drill-core run with threshold and logging-quality guidance.
• Rock Mass Rating (RMR89) calculator — Calculate basic and orientation-adjusted RMR89 with visible component ratings, version boundaries, and non-design limits.
• Point load strength index Is(50) calculator — Calculate equivalent diameter, the 50 mm size correction, and the applicable RMR89 point-load band.
• Rock UCS and uniaxial compressive strength calculator — Calculate direct cylindrical-core intact strength from peak axial load and initial area, with units, geometry, and RMR89 bands.
• Rock weight calculator and density chart — Estimate boulder or rock mass and compare illustrative densities in metric and imperial units.
• Porosity and void ratio calculator — Calculate total porosity and void ratio from density, volumes, porosity, or void ratio with visible formulas.
• Darcy's law groundwater flow calculator — Calculate hydraulic gradient, Darcy flux, discharge, and optional pore-water velocity with explicit hydrogeologic limits.
• Aquifer transmissivity calculator — Solve T = Kb for transmissivity, horizontal hydraulic conductivity, or saturated thickness with mixed units and explicit interpretation limits.
• Radiometric dating and half-life calculator — Explore age, half-life, parent remaining, and corrected radiogenic daughter-to-parent ratio with official sources and laboratory limits.
• Geothermal gradient and formation temperature calculator — Solve temperature, gradient, or true vertical depth with mixed units and explicit BHT, heat-flow, and design limits.
• Hydraulic conductivity and permeameter calculator — Calculate constant-head or falling-head laboratory hydraulic conductivity with common output units and explicit test-validity limits.
• Lugeon and packer test calculator — Normalize rock-mass water take from effective pressure, stabilized flow, and isolated interval length with explicit field-test limits.
• Theis equation well drawdown calculator — Calculate idealized confined-aquifer drawdown with the full Theis well function, sensitivity snapshots, and explicit model limits.
• Slope and gradient calculator — Convert rise/run, percent grade, degrees, and ratio with a profile and distance check.
• Latitude longitude coordinate converter — Convert DD, DMS, and DDM privately while preserving datum, coordinate order, source, and accuracy context.
• Map scale and ground distance calculator — Convert map and ground distance or derive a 1:N representative fraction with metric, imperial, and resizing safeguards.
• Distance between coordinates calculator — Calculate private great-circle distance, initial and final bearing, and midpoint between two latitude/longitude points.
• True thickness calculator — Correct an apparent drill or outcrop interval using a known intersection angle or full plane and line orientations.
• WGS 84 UTM coordinate converter — Convert latitude/longitude and UTM easting/northing privately with automatic zones and explicit datum limits.
• Ore grade unit converter — Convert ppm, ppb, percent, g/t, mg/kg, kg/t, and troy ounces per short ton without exposing an assay value.
• Contained metal calculator — Calculate private arithmetic contained mass from matched tonnage and grade with explicit professional limits.
• Mining cut-off grade and break-even grade calculator — Calculate a simplified single-product break-even head grade with transparent cost, price, recovery, payability, and reporting limits.
• Mine dilution and ore loss calculator — Calculate recovered ore, ore loss, added diluent, final mined tonnage, and diluted grade while making the percentage denominator explicit.
• Mining stripping ratio calculator — Calculate a private waste-to-ore ratio from mass or bank volume with optional density conversion and explicit planning limits.
• Weighted average drill intercept grade calculator — Length-weight assay intervals with gap, overlap, true-width, and reporting safeguards.
• Drill hole desurvey calculator — Calculate a private minimum-curvature borehole trace, toe coordinates, TVD, displacement, dogleg, and dogleg severity.
• Earthquake magnitude and energy calculator — Compare two moment magnitudes, approximate radiated energy, seismic moment, and logarithmic scale with explicit intensity and hazard limits.
• How to clean rocks and minerals — Screen hazards, stability, treatments, water, chemicals, vibration, abrasion, and conservation limits before cleaning.
• Is my rock valuable? — Separate identification, provenance, scientific value, gem reports, appraisal, representative assay work, and defensible market evidence.
• Igneous rock identification chart — Cross texture with felsic, intermediate, mafic, or ultramafic composition to shortlist common rock names.
• Sedimentary rock identification chart — Use clast size, rounding, fissility, fossils, and composition to shortlist common sedimentary rocks.
• Metamorphic rock identification chart — Use foliation, grain size, banding, recrystallized texture, and composition to shortlist metamorphic rocks.
• Fossil identification guide — Separate body fossils, trace fossils, and pseudofossils; compare common groups, preservation, and responsible reporting.
• Rock identification quiz — Practice texture-first reasoning across igneous, sedimentary, and metamorphic rocks in twelve free questions.
• Mineral identification quiz — Practise mineral properties, common look-alikes, and safer identification decisions in twelve free questions.
• Fossil identification quiz — Practise fossil evidence, common groups, preservation, pseudofossils, and responsible field decisions.
• Mineral identification worksheet — Record context, properties, candidates, contradictions, and the safest next test.
• Specific gravity calculator — Calculate specimen SG privately from suspended weights or water displacement.
• Interactive rock cycle — Explore and print the pathways among magma, sediment, and the three rock groups.
• Identification test procedures — Review safer hardness, streak, magnetism, cleavage, density, and other methods.
• Black metallic minerals — Compare common black minerals with a metallic lustre using magnetism, streak, hardness, density, and cleavage before choosing an identification.
• Green minerals — Identify common green minerals by comparing hardness, streak, cleavage, habit, host rock, and reaction to dilute acid—not colour alone.
• Minerals that scratch glass — Learn what a glass scratch test means, which common minerals may scratch glass, and how to avoid confusing a powder mark with a true scratch.
• White minerals — Separate common white and colourless minerals with hardness, cleavage, acid reaction, taste-free testing, and crystal form.
• Vesicular rocks — Identify rocks with gas-bubble cavities by comparing colour, density, vesicle walls, composition, and volcanic context.
• Banded rocks — Interpret banded rocks by separating metamorphic mineral segregation, sedimentary bedding, flow banding, veins, and weathering patterns.
• Red minerals — Compare common red, reddish-brown, and scarlet minerals using streak, hardness, lustre, habit, density, and geologic setting rather than colour alone.
• Blue minerals — Narrow common blue minerals with streak, hardness, cleavage, crystal habit, host rock, and colour distribution instead of relying on hue alone.
• Metallic minerals — Separate common metallic-looking minerals with colour, streak, hardness, magnetism, cleavage, density, tarnish, and host-rock evidence.
• Glassy rocks — Identify glassy rocks and look-alikes by comparing fracture, bubbles, flow structures, inclusions, weathering, density, and field context.
• Foliated rocks — Separate common foliated metamorphic rocks using grain size, cleavage, sheen, mineral alignment, compositional banding, and metamorphic context.
• Porphyritic rocks — Interpret porphyritic texture by comparing phenocryst minerals, groundmass grain size, vesicles, alteration, and intrusive or volcanic field relationships.
• Gold look-alikes — Identify common gold look-alikes by comparing deformation, streak, hardness, crystal shape, sheet cleavage, tarnish, and density before considering an assay.
• Pyrite vs Gold — Compare pyrite and gold using streak, hardness, malleability, crystal shape, density, and glass-scratch tests—plus field safety guidance.
• Quartz vs Calcite — Tell quartz from calcite with hardness, cleavage, fracture, dilute-acid response, and crystal habit using a safe field workflow.
• Magnetite vs Hematite — Separate magnetite from hematite using magnetism, black versus red-brown streak, appearance, formula, and mixed-sample cautions.
• Pyrite vs Chalcopyrite — Separate pyrite from chalcopyrite with hardness, glass and steel tests, crystal form, colour, tarnish, and careful sulfide handling.
• Calcite vs Dolomite — Compare calcite and dolomite using cool dilute acid, powdered-surface response, hardness, cleavage, and mixed-carbonate cautions.
• Gypsum vs Calcite — Tell white or clear gypsum from calcite with fingernail hardness, cleavage, dilute-acid response, and non-destructive checks.
• Galena vs Graphite — Separate lead-gray galena from graphite using heft, cubic versus sheet cleavage, greasy feel, hardness, streak, and lead-safe handling.
• Fluorite vs Calcite — Distinguish fluorite from calcite with four-way versus three-way cleavage, Mohs hardness, dilute-acid response, and UV limitations.
• Halite vs Calcite — Tell halite from calcite safely using cubic versus rhombohedral cleavage, hardness, water solubility, and dilute-acid response—without tasting.
• Biotite vs Graphite — Separate dark biotite mica from graphite using sheet elasticity, paper marks, streak, feel, lustre, and host-rock context.
• Quartz vs Feldspar — Separate quartz from feldspar using cleavage, fracture, crystal shape, striations, transparency, and careful hardness tests.
• Granite vs Diorite — Compare granite and diorite using quartz, potassium feldspar, plagioclase, dark-mineral abundance, texture, and classification limits.
• Marble vs Limestone — Tell marble from limestone using recrystallized texture, fossils, bedding, porosity, calcite reaction, and geologic context.
• Basalt vs Andesite — Compare basalt and andesite using colour index, olivine, pyroxene, plagioclase, silica range, phenocrysts, and classification limits.
• Shale vs Slate — Tell shale from slate using sedimentary bedding, slaty cleavage, strength, surface texture, fossils, and metamorphic context.
• Gneiss vs Granite — Tell gneiss from granite using mineral banding, foliation, grain alignment, interlocking texture, cross-cutting contacts, and metamorphic context.
• Obsidian vs Basalt — Tell obsidian from basalt using glassy versus fine-crystalline texture, fracture, edge translucency, minerals, vesicles, and volcanic context.
• Pumice vs Scoria — Tell pumice from scoria using density, colour, vesicle walls, volcanic composition, texture, and the limits of the float test.
• Agate vs Jasper — Tell agate from jasper using translucency, banding, inclusions, texture, and formation while recognizing mixed and commercial material.
• Meteorite vs Slag — Screen a suspected meteorite against industrial slag using interior bubbles, fusion crust, streak, magnetism, density, context, and laboratory-confirmation limits.
• Chalcopyrite vs Gold — Tell brassy chalcopyrite from native gold using streak, brittleness, tarnish, hardness, deformation, density, grain form, and confirmation limits.
• Mica vs Gold — Tell golden mica flakes from native gold using sheet cleavage, flexibility, streak, deformation, heft, changing reflections, and confirmation limits.
• Meteorite vs Magnetite — Screen a magnetic dark rock for magnetite or a possible meteorite using streak, interior metal, texture, density, crust, and professional confirmation limits.
• Jade vs Serpentine — Compare nephrite or jadeite jade with serpentine and serpentinite using hardness, texture, polish, magnetism, toughness, density, and gem-report limits.
• Sandstone vs Quartzite — Tell quartz-rich sandstone from quartzite using grain-boundary fracture, recrystallized texture, hardness, porosity, bedding, and field-classification limits.
• Ruby vs Garnet — Compare rough ruby and red garnet using hardness, crystal form, pleochroism, specific gravity, geology, treatments, and gem-laboratory limits.
• Quartz vs Glass — Separate quartz from natural or manufactured glass using crystal form, bubbles, mould marks, fracture, context, and a controlled hardness comparison.
• Fossil vs Pseudofossil — Separate fossils from concretions, dendrites and other pseudofossils using repeated anatomy, matrix relationships, context, and responsible reporting.
• Granite vs Basalt — Compare granite and basalt using grain size, felsic and mafic minerals, colour index, cooling setting, field context, and porphyritic exceptions.
• Basalt vs Gabbro — Tell basalt from gabbro using visible crystal size, shared mafic mineralogy, cooling history, vesicles, weathering, and porphyritic exceptions.
• Granite vs Rhyolite — Separate granite from rhyolite using visible crystal size, shared felsic mineralogy, cooling history, porphyritic texture, flow features, and field context.
• Chert vs Flint — Compare chert and flint by host rock, nodule or bed context, colour, cortex, fracture, and regional naming while recognizing substantial overlap.
• Jasper vs Chert — Compare jasper and chert using hematite-rich colour, opacity, sedimentary or hydrothermal context, inclusions, fracture, and naming conventions.
• Agate vs Chalcedony — Compare agate and chalcedony using banding, translucency, cavity structure, fibrous silica texture, inclusions, trade names, and treatment limits.
• Slate vs Phyllite — Tell slate from phyllite using planar versus wavy foliation, dull versus silky sheen, grain visibility, cleavage, metamorphic transitions, and field limits.
• Phyllite vs Schist — Separate phyllite from schist using silky sheen, visible mica flakes, foliation geometry, grain size, porphyroblasts, gradational boundaries, and context.
• Schist vs Gneiss — Compare schist and gneiss using visible platy minerals, schistosity, light-dark compositional banding, splitting behaviour, veins, and metamorphic limits.
• Conglomerate vs Breccia — Tell conglomerate from breccia using gravel-sized clasts, rounded versus angular outlines, matrix support, mixed populations, origin, and field context.
• Sandstone vs Siltstone — Separate sandstone from siltstone using dominant grain size, hand-lens visibility, surface texture, bedding, mixed boundaries, weathering, and lab limits.
• Siltstone vs Shale — Tell siltstone from shale using dominant fine-grain size, faint grit, fissility, lamination, blocky fracture, weathering, naming conventions, and analysis.
• Shale vs Mudstone — Separate shale from mudstone using repeated fissility, lamination, blocky fracture, fine grain size, weathering, overlapping terminology, and field context.