Gleamite

Identify a crystal by habit, color and hardness

How to identify crystals comes down to four questions about the piece in your hand: what shape the faces make, what color it is, how much light passes, and what a steel nail does. This crystal identifier asks them in that order and ends on a name with the check that confirms it, not a label to take on faith.

How to identify crystals: work the key

Crystals are friendlier to identification than rocks because habit carries real signal: a six-sided point, a cube and a silky blade belong to different minerals before color is even considered. The key starts there, then asks color, then how much light passes, then what a steel nail does. Nothing leaves your browser and nothing needs a photo — the whole thing is a printed decision tree you click through.

  1. Step 1

    Does the piece have flat natural faces, and what shape do they make?

    Natural faces grew that way and meet at repeatable angles. Polished flats are wavy, scratched and meet at whatever angle the tumbler left.

  5. Step 5

    No natural faces: hold it up to a lamp. How much light gets through?

  6. Step 6

    Colorless points: does a steel nail scratch them?

    Scratch a hidden spot near the base, never a display face. Quartz is 7 on the Mohs scale, a steel nail about 5.5, calcite 3 and gypsum 2.

Start over

One warning the key repeats: scratch a hidden spot near the base, never a display face. A hardness test is permanent, and a stone worth identifying is worth not damaging. For the quartz family in full — every variety, every fake and the cleavage-flash trick that retires feldspar — see how to identify quartz.

Crystal identification chart: results and checks

Every branch of the key ends in this chart, one row per crystal people actually find. It is a chart of verdicts, not of properties: the table for browsing luster, hardness and streak of rock-forming minerals is the mineral identification chart. What this chart adds is the confirming test for each candidate, and what the answer becomes when that test fails.

CandidateThe check that confirms itIf the check fails
Clear or milky quartzIt scratches glass, a steel nail leaves nothing, and a broken edge is a curved shell rather than a flat mirror-like face.A flat face flashes light like a mirror when you turn it: that is cleavage, and quartz has none — try feldspar or calcite.
AmethystPurple that varies across the crystal, and it scratches glass. Natural color zones unevenly and ignores cracks.Color that is even everywhere except the cracks, where it pools darker, is dye. Uniform deep purple on a cheap tumbled stone deserves that suspicion.
CitrineIt scratches glass, so it belongs to the quartz family. Natural citrine is usually a pale smoky yellow spread evenly through the crystal.Deep orange-brown with a white base and a color that stops abruptly near the tip is heat-treated amethyst, which is what most commercial citrine is.
Smoky quartzIt scratches glass, and thin edges still pass brown light when held against a lamp even when the crystal looks black.No light at any edge and a curved glassy break: read the obsidian row instead.
CalciteA steel nail scratches it, vinegar fizzes on the scratch, and broken pieces are slanted rhombs rather than shells.No fizz and the nail leaves nothing: the piece is quartz wearing calcite colors.
Selenite or satin sparA fingernail scratches it, which almost nothing else on a shelf allows, and it peels into thin flexible blades.A fingernail slides off but a nail marks it: read the calcite row.
FluoriteA steel nail marks the cube faces, corners break away on flat planes, and many specimens glow under a UV lamp.The nail leaves no mark on a cube: it is more likely pyrite under a coating, or quartz.
PyriteDrag it on unglazed tile: pyrite leaves a greenish-black streak. Gold leaves gold, and the cube faces of pyrite carry fine parallel striations.A yellow streak and metal that dents rather than shatters under a pin means gold, and that is a different page.
HaliteLeave a corner in a drop of water for a minute: halite dissolves and dulls, while every other cubic mineral here is unaffected.Water does nothing and the cube is brassy: read the pyrite row.
Muscovite or biotite micaA pin lifts a sheet that bends and springs back instead of crumbling, and the sheet is thin enough to see through.Sheets that snap rather than bend, with a silky surface, are selenite.
MalachiteA drop of vinegar on a hidden spot fizzes, because malachite is a carbonate. Keep it to a hidden spot: acid etches the polish permanently.No fizz on green banding means dyed howlite, green jasper or glass, none of which carry carbonate.
Rose quartzIt scratches glass and the pink is cloudy and evenly diffuse, with a faint glow when a light is held behind a thin edge.Hot even pink concentrated along cracks is dyed quartzite or dyed calcite; check the nail as well.
AgateIt scratches glass, and the bands are curved and concentric — they follow the shape of the cavity the agate grew in.Straight parallel stripes and no translucency at the edge point to banded jasper or dyed chalcedony instead.
Nephrite, jadeite or serpentineA steel nail settles it: jade is 6 to 7 on the Mohs scale and shrugs the nail off, while serpentine runs from 2.5 to 5.5 and takes a mark.The nail marks it and the surface feels soapy: it is serpentine, sold as jade more often than any other stone.
HematiteThe streak on unglazed tile is red-brown no matter how silver the surface looks, and the piece is unusually heavy for its size.A black streak and a strong pull on a magnet mean magnetite; a greenish-black streak on brassy metal means pyrite.
Lapis lazuli or sodaliteLook for brassy metallic flecks with a lens: pyrite inclusions are normal in lapis and absent in sodalite, which shows white veining instead.Even blue with no flecks and no veining, at a suspiciously low weight, is dyed howlite or blue glass.
Turquoise or dyed howliteTouch a hidden spot with acetone on a cotton swab. Dyed howlite gives up blue color onto the swab; turquoise does not.No color transfers, but the stone is uniformly plastic-bright with a seam: it is likely reconstituted or imitation, and only a lab can grade the rest.
ObsidianA fresh chip is a curved glassy hollow with no crystals and no round bubbles, and thin edges pass a little light.Round bubbles inside mean manufactured glass or slag; a dull grainy break means it is a rock, not a natural glass.

If the piece is dull, grainy or clearly a mixture of minerals, it is a rock rather than a crystal — the rock identifier key asks the right questions for those, and the rock identification chart is the manual lookup. Cut and faceted stones from jewelry play by different rules again; see the gem identifier for where physical checks stop being safe to run.

Dyed, baked and glass lookalikes

The crystal trade has three standard tricks, and all three fail simple checks. Dyed howlite impersonates turquoise: white stone, spidery veins, soaked in blue — acetone on a cotton swab lifts the color. Baked amethyst impersonates citrine: heating turns purple quartz orange, which is why deep-orange “citrine” points with white bases dominate gift shops. Glass impersonates everything: look for round air bubbles inside, which no natural crystal has.

Natural color zones unevenly and ignores cracks. Dye does the opposite: even everywhere except the cracks, where it pools darker.

None of this requires a lab. It requires knowing which check applies to which claim — which is exactly what the last two columns of the key results carry, and what the app comparison checks the other identifiers for.

How the photo identifier fits in

A photo does the first pass and the key does the last one. Color, transparency and the shape of the faces are exactly what a camera reads well, so an app can cut two hundred candidates to three; hardness, fizz and where the color sits are what a camera cannot read at all, so the finish is physical either way.

  1. Step 1Shoot against daylightTransparency is half the evidence. Photograph the crystal on a plain surface, then once more held up to light so the app sees what passes through.
  2. Step 2Read the candidatesRanked matches with reference photos: natural zoning patterns, typical habits, and the lookalike each candidate is confused with.
  3. Step 3Check the color placementNatural color zones unevenly. Color pooled in cracks means dye; the app flags candidates where this check matters.
  4. Step 4Confirm with hardnessA steel nail separates the quartz family from calcite and glass impostors in five seconds. Each match says what should and should not scratch.

What this page is not

Gleamite identifies what a crystal is: species, variety, the checks that confirm it. Pages about what crystals mean, heal or attract are a different subject with different authors, and nothing here speaks to it. If a seller’s metaphysical claims come attached to a mineralogical one — “genuine citrine”, “natural turquoise” — this page and the key above can test the second half. That is the half you pay for.

Questions people ask

How can I tell what crystal I have?
Start with shape, then color, then transparency, then hardness — that order eliminates the most candidates fastest. Quartz varieties scratch glass and resist a steel nail; calcite looks similar but a nail scratches it easily and vinegar makes it fizz. The key on this page asks those four questions and names the check that settles each answer.
Is there a free app to identify crystals?
Free browser uploaders identify crystals from a photo at a desk, and phone apps in this category install free and charge inside for unlimited scans. Either way the shortlist still needs confirming, and the hardness and color-placement checks on this page cost nothing and settle what a photo cannot.
How do I know if a crystal is real or dyed?
Look at where the color sits. Dyed stones concentrate color in cracks and pores, show uniform saturated hues that natural stones rarely reach, and sometimes bleed onto a damp white cloth. Natural amethyst shows uneven purple zoning; a uniformly deep-purple, cheap tumbled stone deserves suspicion.
What is the difference between a crystal and a rock?
A crystal is a single mineral with an ordered internal structure, sometimes showing visible faces; a rock is a mixture of mineral grains. Granite is a rock made of quartz, feldspar and mica grains — each grain is a crystal. The distinction decides which checks apply, which is why identification starts there.
Can a photo identify a crystal for certain?
No, and any tool claiming certainty is overreaching. A photo narrows candidates by color, transparency and habit, and it does that well. Certainty comes from physical properties — hardness, streak, specific gravity — or from a gemological lab when the stone might be valuable. The honest workflow is photo first, one test after.
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