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Malachite

Last updated: April 2026

A green copper carbonate hydroxide mineral, known for its distinctive banded appearance.

Malachite has a specific gravity of 3.80 and a refractive index of 1.655–1.909, with a Mohs hardness of 3.5–4.0. It is biaxial −.

Physical & Optical Properties

RI Range1.655–1.909
SG Range3.60–4.05
SG Typical3.80
Hardness (Mohs)3.5–4
Crystal SystemMonoclinic
Optic CharacterDR Biaxial (−)
Birefringence0.254
Dispersion0.025
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterInert
PleochroismNone
ColorsGreen
SpeciesMalachite
Green

Measured with a polariscope, a refractometer, a hydrostatic balance, a Chelsea filter, a UV torch, a loupe, a darkfield loupe and a spectroscope — step-by-step for each.

Through the refractometer

Malachite reads 1.655 1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 1.80 1.909 REFRACTIVE INDEX DORotate the stone through a full 360°, reading at every 45°. SEEOne boundary, at 1.655. However far you rotate, a second onenever appears. MEANSA trap, and here is how to escape it. This stone IS doublyrefractive, but its upper edge sits at 1.909 — past the 1.81ceiling — so the instrument cannot show it. One edgetherefore does NOT prove singly refractive. Move to a secondfacet and read again: if a single edge still holdsabsolutely still on both, that is your answer, and ifanything moves it never was singly refractive. Computed from gems.json — edge positions are arithmetic, not drawn. RI increases upward; the field above the boundary is the dark one.

Drawn from the refractive index above, on a 1.40–1.81 scale. How to take this reading.

Through the polariscope

Malachite No reading ANY POSITION — THE STONE BLOCKS THE LIGHT BETWEEN CROSSED POLARS Malachite is opaque, so no light reaches the analyser. The field stays dark in every position — not because the stone is singly refractive, but because the test cannot be run on it at all. SR, DR and aggregate cannot be separated this way. Computed from optic character and transparency in gems.json. A polariscope separates singly refractive, doubly refractive and aggregate — it does not show the optic sign.

Drawn from the optic character and transparency above. A polariscope separates singly refractive, doubly refractive and aggregate; the optic sign needs a conoscope. How to take this reading.

Specific gravity, and what it rules out

Malachite SG 3.60–4.05 WHERE IT SITS, AND WHAT ELSE IS THERE 1.0 2.0 3.0 4.0 5.0 SPECIFIC GRAVITY 33 other species in the table overlap this range, so a reading here narrows the field to 34 rather than naming the stone. This is the crowded part of the scale — the same careful measurement is worth far more higher up. Computed from the specific-gravity range in gems.json. Hydrostatic weighing — the bench method this site recommends; heavy liquids are toxic and regulated. Faint ticks are the other species in the table.

Drawn from the specific-gravity range above, against every other species in the table. How to take this reading.

Through the dichroscope

Malachite No reading NO LIGHT THROUGH THE STONE Malachite is opaque. A dichroscope reads light that has passed THROUGH the stone, so there is nothing to split and no reading to take — the same limit that rules out the polariscope. Computed from pleochroism and pleochroic colours in gems.json. Window tints are derived mechanically from the colour words, not chosen; a neutral pair depicts no colour at all.

Drawn from the pleochroism above. Two windows that match mean either no pleochroism or the wrong angle — turn the instrument to tell. How the dichroscope compares.

Key Differentiators

Natural vs. Synthetic

Synthetic malachite is commercially available (Precipitation synthesis (rare)). Distinguishing natural from synthetic typically requires microscopic examination of internal features.

Loupewise Pro includes a two-phase natural vs. synthetic testing protocol for Malachite.

Treatments

Measurement Guides

How to Identify a GemstoneHow to Measure Specific GravityHow to Use a RefractometerUV Fluorescence Testing

Identifying a malachite? Loupewise walks through these tests in order — RI, SG, fluorescence, and more.

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Studying for the GIA, FGA, or FEEG practical? Malachite is one of the 132 species in Loupewise’s drill and exam pool — practice identifying it from its measured properties under timed exam conditions.

Practice exams →