Mineral Identifier

Identify mineral species by selecting physical properties like hardness, color, luster, streak, and cleavage. Narrow down possibilities from thousands of minerals to find your specimen.

Identification

Select Properties

Matching Minerals

How to Use

  1. 1
    Select observable physical properties

    Choose the hardness, luster, color, streak color, and cleavage or fracture pattern of your specimen. Use a pocket knife (5.5 Mohs), fingernail (2.5), and copper coin (3) to bracket hardness before entering values.

  2. 2
    Apply additional diagnostic tests

    Check for special properties such as magnetism, fluorescence, taste (safe minerals only), acid reaction, or specific gravity feel. These secondary properties often distinguish look-alike minerals that share the same hardness and color.

  3. 3
    Review the ranked candidate list

    The tool returns a ranked list of matching mineral species with match scores. Compare your specimen against the illustrated descriptions and eliminate candidates until the most probable identification emerges.

About

Mineral identification is a foundational skill in geology, materials science, and gemology that relies on systematic observation of physical and chemical properties. Unlike rocks, which are aggregates of multiple minerals, each mineral species is defined by a unique chemical formula and crystalline atomic arrangement. These defining characteristics manifest as measurable physical properties—hardness, cleavage, specific gravity, luster, streak, and crystal form—that allow confident identification in the field and laboratory.

The Mohs hardness scale, proposed by Friedrich Mohs in 1812, ranks minerals on a relative scratch-resistance scale from 1 (talc) to 10 (diamond). This empirically derived scale remains the most practical field tool for narrowing mineral candidates. Combined with streak color—which is independent of specimen color because it reflects the true pigment of the powdered mineral—hardness testing eliminates the majority of false matches rapidly. Specific gravity, the ratio of a mineral’s weight to the weight of an equal volume of water, provides a sensitive compositional proxy: native gold (SG ≈19.3) is immediately distinguished from pyrite (SG ≈5.0) by heft alone.

Modern mineral databases cross-reference more than 5,700 approved mineral species recognized by the International Mineralogical Association. Systematic identification tools leverage multi-property filtering to reduce candidate pools from thousands of species to a handful, integrating crystallographic data, optical properties, and chemical group membership to guide collectors, students, and professionals toward confident determinations.

FAQ

Why can the same mineral appear in many different colors?
Color in minerals arises from multiple mechanisms, making it one of the least reliable identification properties. Idiochromatic minerals like malachite derive color from essential chemical constituents, so they are consistently green. Allochromatic minerals such as quartz gain color from trace impurities—iron produces amethyst purple while titanium creates rose quartz. Physical effects like thin-film interference produce labradorescence in feldspar and iridescence in precious opal. Because color varies so widely, mineralogists rely on streak—the color of the powdered mineral—as a more consistent diagnostic property.
What does luster describe and why does it matter?
Luster describes how a mineral surface interacts with light, reflecting the surface’s physical structure and the mineral’s optical constants including refractive index and reflectivity. The two primary categories are metallic, where the mineral reflects light like polished metal, and non-metallic, which includes subtypes such as vitreous (glass-like), resinous, pearly, silky, adamantine (diamond-like), and dull or earthy. Metallic luster is a strong indicator of sulfide, oxide, or native element minerals. Adamantine luster points toward high-refractive-index minerals including diamond, sphalerite, and cerussite. Correctly assessing luster on a fresh surface rather than a weathered face significantly narrows the identification field.
How does cleavage differ from fracture in minerals?
Cleavage is the tendency of a mineral to break along flat planes defined by weak atomic bonds parallel to crystallographic directions, producing smooth, reflective surfaces. Fracture describes breakage along irregular, random surfaces not governed by crystal structure. Cleavage is characterized by the number of directions and the angles between them: calcite shows perfect rhombohedral cleavage in three directions at 75°, while halite cleaves perfectly in three directions at 90°. Conchoidal fracture—curved, shell-like surfaces—is diagnostic for quartz and obsidian. Identifying cleavage requires examining multiple broken faces and noting whether reflections appear simultaneously as the specimen is rotated.
Can two minerals share identical hardness, color, and luster?
Yes, which is why mineralogists employ a battery of tests rather than relying on any single property. Pyrite and chalcopyrite both display metallic luster and brassy-yellow color, but pyrite is harder (6–6.5 vs. 3.5–4) and produces a greenish-black streak rather than chalcopyrite’s black streak. Calcite and dolomite share white color, vitreous luster, and similar hardness near 3–3.5, but calcite effervesces vigorously in cold dilute hydrochloric acid while dolomite reacts only when powdered or in warm acid. Specific gravity, crystal habit, fluorescence, and association with other minerals in the same deposit all contribute to confident identification when primary properties overlap.
What is the Dana classification system used in mineralogy?
The Dana classification system, first published by James Dwight Dana in 1837 and periodically updated, organizes minerals into classes based on chemical composition and crystal structure. The eight primary classes are native elements, sulfides and sulfosalts, oxides and hydroxides, halides, carbonates, sulfates, phosphates, and silicates, with silicates further subdivided by silicate anion structure into nesosilicates, sorosilicates, cyclosilicates, inosilicates, phyllosilicates, and tectosilicates. The parallel Strunz system, used in European literature and the Mineralogical Society of America’s “Mineral Data” database, uses a similar chemical-structural hierarchy. Both systems allow rapid cross-referencing of physical properties with chemical composition, which is essential for systematic identification.
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