Mineral identifier by photo

Use this free online mineral identifier to explore a mineral by photo. Upload a whole specimen and close views of crystal shape, luster or existing break surfaces, then compare possible matches and ask a follow-up. The tool is a starting point for mineral comparison; mixed rocks may need a broader identification.

A mineral identifier is most useful when the photograph shows one reasonably distinct material. A rock commonly contains several minerals, so a sparkling patch in granite, a white vein in sandstone, or a dark coating on a pebble is not automatically one named mineral. Begin with a whole-specimen image. Then decide whether the question concerns a loose crystal, a repeated grain in a matrix, a vein, a coating, or a mixed rock surface.

The National Park Service describes minerals through properties such as cleavage, luster, hardness, streak, and specific gravity. A camera can help document some surface properties, especially luster, shape, and visible break patterns. It cannot measure hardness, streak, density, chemical composition, or crystal structure. Keep those missing properties out of the conclusion rather than filling them in from color or a seller label.

Take one photo that includes the whole specimen and scale, then a sharp close view of the feature you want to compare. A third view can show an already exposed edge, the boundary with the host rock, or the feature under angled light. Upload one to three photos of the same specimen. JPG, PNG, and WebP images up to 10 MB are supported. A plain background and diffuse daylight make luster and color easier to judge.

Do not crop away the matrix. A clear grain embedded in an igneous rock, a crystal lining a cavity, and a polished loose stone each need different explanations. Photograph the contact between the suspected mineral and surrounding material. If a coating flakes or follows cracks, describe that visible relationship; it may be weathering or another material rather than the mineral you first noticed.

Look for repeated flat faces, repeated angles, a prismatic form, platy layers, or an irregular fracture. Cleavage refers to a tendency to break along weak planes, while a curved broken surface may suggest fracture rather than cleavage. On a damaged specimen, neither feature may be clear. Say that the edge is chipped, weathered, or unavailable instead of calling every flat-looking chip a cleavage plane.

Use light from the side as well as light from above. A surface can appear glassy, pearly, metallic, dull, or earthy, but reflection also changes with dust, polish, water, and camera exposure. Compare a photo in ordinary diffuse light with one gently angled toward a window. A conclusion should describe the observed reflection rather than promote it into an unverified mineral name.

Color is a useful note but a poor final discriminator. Quartz, feldspar, calcite, glass, weathering products, and coatings can overlap in white, gray, brown, green, or pink tones. Instead, make two short lists: features that support a candidate and features that conflict with it. A candidate becomes weaker when it needs a property that is hidden or when another explanation better fits the host rock and visible surface.

For example, a translucent grain with curved fracture may keep quartz on the list, while a material with obvious repeated flat break directions may call for a feldspar or calcite comparison. A clear substance with bubbles, a seam, or a manufactured mounting may call for glass or resin as an alternative. None of those visual clues is absolute; the point is to make the uncertainty specific.

For natural growth faces, try the crystal identifier. For a clear crystal or vein, compare candidates with the quartz identifier. For a rock made of interlocking grains, use the quartzite identifier.

A hand lens, ruler, and ordinary light are enough for a useful follow-up. Show the grain scale, rotate the specimen, and photograph an existing edge. Record whether a feature repeats across several grains or occurs only in one spot. Do not scratch an unknown specimen, create powder, apply acids, or break a sample to obtain an online answer. Historic fabric, protected material, and samples from parks or private land should be photographed without alteration.

If you already have a professionally recorded hardness, streak, or chemical result, keep it separate from the photo observation and identify its source. Do not infer a result because an object resembles an online example. The next productive question is often visual: is the apparent crystal a single grain, a vein filling, or a reflective coating? Another well-framed photo can answer that more safely than an improvised test.

A weathered outdoor surface may conceal the fresh material beneath it. A polished countertop can make separate grains look more uniform, and a close crop can remove the scale needed to distinguish a crystal from fine sparkle. If the material is opaque, covered by dirt, or only visible in one blurred image, the useful result may be “possible mineral feature; more evidence needed.” That is better than turning a weak visual resemblance into a collection label.

Treat commercial names with caution. “Crystal,” “stone,” and product names can describe appearance or marketing rather than mineralogy. A photograph cannot establish natural origin, treatment, provenance, rarity, authenticity, value, or suitability for jewelry. If those questions matter, retain the photos and seek a qualified mineralogist, museum, university collection, or laboratory with the specimen available for examination.

Write down where on the specimen the feature occurs, which image shows it best, and what remains uncertain. Notes such as “clear grains in a white vein,” “dark reflective flakes in coarse rock,” or “flat-looking chips on a weathered edge” preserve evidence without pretending to have completed a test. Keep location context separate from identity: gravel and landscaping material may have been transported.

When a result offers a candidate and alternatives, compare the visible evidence before saving it. If a later image or expert examination changes the conclusion, keep the earlier note as a dated provisional observation. A useful mineral record shows how a name was reached, what did not fit, and which checks were not performed.

A useful question for a later observer is specific: whether the pale material cuts across the rock, whether dark flakes lie in layers, or whether a clear area is a separate grain. Mark the relevant feature with a ruler nearby rather than drawing on the specimen. This creates a repeatable observation trail without changing the object.