vs Sand · card — Alluvium is a deposit type; sand is the grain-size feel within it.

vs Gravel · card — Alluvium often includes gravel lenses — log each layer.

vs Fill · card — Natural river layering vs dumped fill.

vs Cobbles · card — Cobbles are smaller than boulders; boulders are the ones that stop the string.

vs Glacial Till · card — Till mixes fines with stones; boulder beds are dominated by huge rocks.

vs Fill · card — Natural boulder lag vs dumped fill rubble — look for construction debris.

vs Silt · card — Clay makes a longer ribbon and feels sticky; silt is floury and barely holds.

vs Glacial Till · card — Till has mixed stones and grit; clay is smooth fines without cobbles.

vs Sand · card — Clayey sand holds a weak smear; clean sand will not.

vs Sandy Clay · card — Clayey sand is sand-first; sandy clay is clay-first sticky.

vs Loam · card — Clayey sand is sandier and less balanced than loam.

vs Gravel · card — Cobbles are fist-sized and up; gravel is mostly pebble-sized.

vs Glacial Till · card — Clean cobble beds are sorted coarse; till mixes fines with stones.

vs Glacial Till · card — Colluvium is slope debris; till is ice-laid unsorted mix.

vs Fill · card — Colluvium is natural slope waste; fill is man-placed.

vs Alluvium · card — Colluvium is angular/chaotic; alluvium is water-sorted.

vs Sand · card — Dune sand is well-sorted wind-blown; other sands may be dirtier.

vs Loess · card — Dune sand is grit; loess is floury silt.

vs Topsoil · card — Fill looks dumped / mixed; topsoil is a natural dark A-horizon.

vs Glacial Till · card — Till is natural unsorted ice mix; fill has man-made debris or odd layering.

vs Glacial Till · card — Outwash is sorted sand/gravel; till is dirty unsorted.

vs Gravel · card — Outwash is the glacial setting for many gravel packs.

vs Sand · card — Outwash sands are meltwater-laid — log sorting and water.

vs Clay · card — Till looks “dirty” with stones in fines; clay is smooth without cobbles.

vs Gravel · card — Till mixes fines with stones; gravel is mostly coarse with little clay matrix.

vs Sand · card — Gravel is pebble-sized and up; sand is finer grit without pebbles.

vs Glacial Till · card — Clean gravel is mostly coarse; till is a dirty unsorted clay-to-boulder mix.

vs Sand · card — Gravelly sand has pebbles; clean sand does not.

vs Gravel · card — Gravelly sand is sand-first; gravel is pebble-first.

vs Glacial Outwash · card — Often the feel inside glacial outwash packs.

vs Limestone · card — Hardpan is a cemented soil layer; limestone is true bedrock carbonate.

vs Sandstone · card — Hardpan sits in the soil profile; sandstone is bedded sedimentary rock.

vs Clay · card — Lacustrine is the lake setting; clay is the feel.

vs Silt · card — Same — log lacustrine when the deposit context is clear.

vs Glacial Till · card — Lake fines are sorted; till is unsorted.

vs Clay · card — Loam ribbons short and has some grit; clay is stickier and smoother.

vs Silt · card — Loam has a bit of grit and stick; silt is almost all flour feel.

vs Sand · card — Loam holds a short ribbon; sand will not ribbon at all.

vs Silt · card — Loess is a thick wind-blown unit; silt is the grain-size feel in any deposit.

vs Clay · card — Loess is floury silt; clay is sticky and ribbons longer.

vs Peat / Organic · card — Muck is fine organic mud; peat is fibrous sponge.

vs Clay · card — Muck is organic-rich; clay is mineral sticky fines.

vs Topsoil · card — Peat is thick organic sponge; topsoil is thinner mineral soil with organics.

vs Clay · card — Peat is lightweight and fibrous; clay is heavy and sticky mineral fines.

vs Saprolite / Residuum · card — Residual soil is the soil profile; saprolite is rotten rock with fabric.

vs Topsoil · card — Topsoil is the dark A-horizon; residual soil is the whole weathered profile.

vs Clay · card — Many residual soils are clay-rich — log the feel and parent rock.

vs Gravel · card — Sand is grit you can mostly pinch; gravel is pebble-sized and larger.

vs Sandstone · card — Sand is loose grains; sandstone is cemented chips or a solid piece.

vs Clay · card — Sandy clay has grit; pure clay is smooth.

vs Clayey Sand · card — Sandy clay ribbons; clayey sand barely holds and feels sandier.

vs Loam · card — Sandy clay is stickier than loam.

vs Clay · card — Saprolite retains rock structure/ghosts; clay is structureless sticky fines.

vs Granite · card — Saprolite digs soft; fresh granite is hard crystalline chips.

vs Schist · card — Saprolite is rotten and soft; schist is hard flaky rock.

vs Clay · card — Silt barely ribbons and feels floury; clay is sticky and ribbons longer.

vs Sand · card — Silt has little grit; sand has obvious grains and will not ribbon.

vs Siltstone · card — Silt is soft soil; siltstone is hard rock chips from the bit.

vs Clay · card — Silty clay has slight flour feel; pure clay is smoother sticky.

vs Silt · card — Silty clay ribbons sticky; silt barely holds.

vs Loam · card — Silty clay is stickier than loam.

vs Sand · card — Silty sand has floury fines; clean sand is just grit.

vs Silt · card — Silty sand is still grainy; silt is mostly flour.

vs Clayey Sand · card — Silty sand feels floury; clayey sand feels sticky binder.

vs Loam · card — Topsoil is darker and more organic; loam is the balanced mineral mix below or beside it.

vs Peat / Organic · card — Topsoil is thin mineral soil with organics; peat is thick spongy organic matter.

vs Fill · card — Topsoil is natural A-horizon; fill is dumped / mixed and often has debris.

vs Basalt · card — Amphibolite is metamorphic crystalline; basalt is finer volcanic.

vs Diabase / Gabbro · card — Amphibolite is metamorphic fabric; diabase is intrusive igneous texture.

vs Schist · card — Amphibolite is darker/heavier amphibole rock; schist is mica-flaky.

vs Basalt · card — Andesite is lighter gray intermediate; basalt is darker mafic.

vs Rhyolite · card — Andesite is darker/more mafic than rhyolite.

vs Diabase / Gabbro · card — Andesite is volcanic fine; diabase is intrusive crystalline.

vs Gypsum · card — Anhydrite is harder; gypsum scratches with a fingernail.

vs Limestone · card — Anhydrite does not fizz; limestone does.

vs Sandstone · card — Arkose is feldspar-rich sandstone; generic sandstone may be quartz-rich.

vs Granite · card — Arkose is sedimentary grit; granite is interlocking crystals.

vs Diabase / Gabbro · card — Basalt is finer volcanic; diabase is coarser intrusive equivalent.

vs Shale · card — Basalt is hard dark crystalline; shale is soft and fissile.

vs Limestone · card — Basalt is dark igneous (no fizz); limestone is carbonate.

vs Conglomerate · card — Breccia has angular clasts; conglomerate has rounded pebbles.

vs Fault Gouge / Shear Zone · card — Fault breccia is tectonic; sedimentary breccia is depositional.

vs Limestone · card — Chalk is soft and often white/porous; typical limestone is harder.

vs Marl · card — Chalk is cleaner carbonate; marl is chalky mix with clay.

vs Limestone · card — Chert is glassy/hard silica (no fizz); limestone fizzes and is duller.

vs Quartzite · card — Chert is finer / glassy nodules or beds; quartzite is metamorphosed sandstone.

vs Limestone · card — Cherty limestone has silica nodules that eat bits.

vs Chert · card — Chert nodules inside limestone vs pure chert beds.

vs Mudstone / Claystone · card — Often used interchangeably; claystone emphasizes clay mineralogy.

vs Shale · card — Claystone is blocky; shale is fissile.

vs Clay · card — Claystone is rock; clay is soft soil.

vs Shale · card — Coal is lightweight and sooty; dark shale is heavier rock that flakes.

vs Peat / Organic · card — Coal is lithified carbon; peat is soft unconsolidated organic.

vs Gravel · card — Conglomerate is cemented rock; gravel is loose overburden.

vs Sandstone · card — Conglomerate has pebble-sized clasts; sandstone is sand-sized grit.

vs Basalt · card — Diabase shows visible crystals; basalt is finer / aphanitic.

vs Granite · card — Diabase is dark mafic; granite is light speckled felsic.

vs Limestone · card — Stronger fizz leans limestone; weaker leans dolostone.

vs Dolostone · card — Dolomitic limestone is the in-between log call.

vs Limestone · card — Dolostone: weak/slow fizz. Limestone: strong fizz. Both look gray/tan in the field.

vs Breccia · card — Gouge is fine crushed flour; fault breccia is coarser angular fragments.

vs Clay · card — Gouge can feel clayey but sits in a structural seam.

vs Shale · card — Gouge is tectonic crush; shale is bedded sedimentary.

vs Limestone · card — Same fizz family — fossiliferous calls out visible fossils.

vs Chalk · card — Fossiliferous limestone is usually harder than chalk.

vs Granite · card — Gneiss is banded; granite is randomly speckled crystals.

vs Schist · card — Gneiss is chunky/banded; schist is more flaky and shiny with mica.

vs Gneiss · card — Granite is speckled without strong bands; gneiss shows light/dark layering.

vs Sandstone · card — Granite chips are crystalline and glassy; sandstone is gritty cemented sand.

vs Granite · card — Field crews often log both as granite-family crystalline.

vs Diabase / Gabbro · card — Granodiorite is lighter speckled felsic; diabase is dark mafic.

vs Sandstone · card — Graywacke is dirty/muddy sandstone; cleaner sandstone shows clearer grit.

vs Shale · card — Graywacke is gritty rock; shale flakes soft.

vs Basalt · card — Greenstone is metamorphosed; basalt is fresher volcanic.

vs Amphibolite · card — Greenstone is lower-grade green meta-mafic; amphibolite is higher-grade.

vs Schist · card — Greenstone is tougher/less mica-flaky than green schist.

vs Limestone · card — Gypsum scratches easy and does not fizz; limestone is harder and fizzes.

vs Chalk · card — Gypsum is sulfate evaporite; chalk is soft carbonate that fizzes.

vs Chert · card — Hornfels is contact-metamorphic; chert is sedimentary silica.

vs Basalt · card — Hornfels is baked country rock; basalt is volcanic.

vs Sandstone · card — Log each hard grit bed.

vs Shale · card — Log each soft flake bed.

vs Siltstone · card — Finer hard beds may be siltstone in the stack.

vs Dolostone · card — Limestone fizzes hard with dilute HCl; dolostone fizzes weak or slow.

vs Sandstone · card — Limestone is dull carbonate (fizzes); sandstone is gritty and usually does not.

vs Limestone · card — Marble is crystalline/sugary; limestone is duller sedimentary carbonate.

vs Quartzite · card — Marble fizzes; quartzite does not.

vs Chalk · card — Marl has more clay feel; chalk is cleaner soft carbonate.

vs Clay · card — Marl is rock/sediment with carbonate; clay is mineral soil without chalky grit.

vs Limestone · card — Marl is soft and clay-rich; limestone is harder carbonate rock.

vs Gneiss · card — Migmatite shows melt streaks in gneissic host.

vs Granite · card — Migmatite is mixed; granite is more uniform intrusive.

vs Shale · card — Mudstone is blocky; shale splits into thin soft flakes.

vs Clay · card — Mudstone is rock chips; clay is soft soil you can ribbon.

vs Siltstone · card — Mudstone is smoother/finer; siltstone has slight grit.

vs Shale · card — Oil shale is organic-rich; normal shale is less sooty/oily.

vs Coal / Lignite · card — Oil shale is rock that flakes; coal is lighter carbonaceous seam.

vs Limestone · card — Oolitic notes the grain type; still limestone on the log.

vs Sandstone · card — Ooids can look sandy but fizz; sandstone grit usually does not.

vs Granite · card — Pegmatite is giant-crystal granite-family rock.

vs Quartzite · card — Pegmatite has mixed crystals; quartzite is sugary meta-sandstone.

vs Slate · card — Phyllite has silky sheen; slate is duller.

vs Schist · card — Phyllite mica is finer; schist shows obvious mica flakes.

vs Sandstone · card — Quartzite is much harder / glassy; sandstone is gritty cemented sand.

vs Chert · card — Quartzite looks sugary metamorphic; chert is finer glassy silica.

vs Granite · card — Quartzite lacks granite’s mixed crystal speckles.

vs Granite · card — Rhyolite is finer volcanic; granite is coarse intrusive.

vs Tuff / Volcanic Ash Rock · card — Rhyolite is lava rock; tuff is ash rock.

vs Andesite · card — Rhyolite is lighter felsic; andesite is intermediate gray.

vs Gypsum · card — Salt tastes salty and is more soluble; gypsum is sulfate.

vs Anhydrite · card — Salt is softer and soluble; anhydrite is harder sulfate.

vs Granite · card — Sandstone is cemented grit; granite is interlocking crystals (glassy quartz).

vs Limestone · card — Sandstone is gritty; limestone is dull carbonate and usually fizzes with dilute acid.

vs Siltstone · card — Sandstone shows sand grains; siltstone is finer and less obviously sandy.

vs Sand · card — Sandstone is cemented or chip-like; sand is loose grains.

vs Gneiss · card — Schist is flaky/shiny; gneiss is thicker-banded and more blocky.

vs Granite · card — Schist splits along shiny layers; granite is speckled and massive.

vs Greenstone · card — Serpentinite is softer/soapier ultramafic alterite.

vs Schist · card — Serpentinite can shear; schist is mica foliation.

vs Siltstone · card — Shale flakes and splits thin; siltstone chips are harder and slightly gritty.

vs Clay · card — Shale is rock flakes from the hole; clay is soft soil you can ribbon by hand.

vs Shale · card — Siltstone is less fissile and slightly gritty; shale splits into soft thin flakes.

vs Sandstone · card — Siltstone is very fine; sandstone shows visible sand grains.

vs Silt · card — Siltstone is hard rock; silt is soft soil with a flour feel.

vs Shale · card — Slate is harder and rings; shale is soft and crumbly.

vs Phyllite · card — Slate is duller/finer; phyllite shows silky sheen.

vs Schist · card — Slate is very fine; schist has visible shiny mica flakes.

vs Serpentinite · card — Soapstone is softer talc-rich; serpentinite is tougher serpentine.

vs Schist · card — Soapstone feels greasy soft; schist is harder mica rock.

vs Sandstone · card — Tuff may look sandy but is volcanic ash; sandstone is cemented sediment grit.

vs Basalt · card — Tuff is lighter ash rock; basalt is dark dense lava.

vs Basalt · card — Vesicular calls out the gas holes — mud-loss risk.

vs Tuff / Volcanic Ash Rock · card — Vesicular basalt is lava with holes; tuff is ash.