Malachite is a copper carbonate mineral that forms in botryoidal (grape-like) masses of concentric bands in alternating shades of green. Cut and polished, the bands make patterns that no two pieces share — and that are imitated in cast resin with painted or layered bands, in pressed malachite powder, and in printed plastic. Genuine malachite is not expensive, but the imitations are cheaper still, and the difference is worth knowing.
What malachite is
Copper carbonate hydroxide. Properties: SG 3.6–4.0 (heavy for its size), hardness 3.5–4 (soft), opaque, RI about 1.66–1.91 (of little practical use on an aggregate), and the diagnostic banded structure: curved, concentric bands of light and dark green, often with a fibrous, silky texture visible within each band under magnification, following the botryoidal growth. Effervesces in acid (destructive; not used). Sensitive to heat and acids.
What is sold as malachite
Cast resin. Bands painted or layered in resin; often too regular or too perfectly parallel; bands lack the fine fibrous texture; light in hand (SG about 1.2); warm; may show mould seams and bubbles; fluoresces under UV; a hot needle marks it (not used by the laboratory). The most common imitation in beads and bracelets.
Reconstituted malachite. Malachite powder bound with resin and pressed. Colour is right, weight is intermediate, but the "bands" are absent or blurred into a mottled texture; resin fluorescence; granular under magnification.
Printed or laminated plastic. A malachite pattern printed on plastic beads; bands are two-dimensional and identical bead to bead.
Dyed marble and dyed agate. Banding present but straight or of the wrong character; SG of the host material; dye in fractures.
Glass. Uncommon; bubbles, swirls.
How the laboratory examines it
Weight. Genuine malachite is heavy — SG near 3.8 — and this alone separates it from resin at once. A bracelet of "malachite" beads that is light in hand is resin.
Magnification. Concentric curved bands with a fibrous or silky internal structure and slight irregularities that follow the botryoidal growth. Painted bands are flat, uniformly coloured and lack internal texture.
UV. Malachite is inert; resin and binders fluoresce.
Surface. Genuine malachite takes a high polish but is soft and shows fine scratches with wear; resin shows a plastic lustre.
Report states: natural malachite, reconstituted malachite, or imitation (resin/plastic/other).
Handling and care
Malachite is soft (3.5–4), easily scratched, and damaged by acids, heat and ultrasonic cleaning. It should be wiped clean, kept from perfumes and household chemicals, and stored apart from harder stones. Malachite dust is a copper compound and should not be inhaled; this is a concern for cutters rather than wearers, and finished polished pieces are safe to handle.
Frequently asked questions
Is malachite ever treated?
Wax or resin coating to improve polish is common and minor; it should be disclosed. Dye is unnecessary since the colour is natural.
Can malachite be transparent?
No. Malachite is opaque. A translucent "malachite" is glass or resin.
Why does my malachite bracelet feel light?
Because it is probably resin. Malachite is one of the heavier gem materials for its size.
Does malachite contain copper?
Yes — it is a copper mineral, and its green is copper's colour. Polished pieces are stable and safe to wear.
What is "azurmalachite"?
Natural malachite intergrown with blue azurite, another copper mineral. Genuine, and imitated by resin with blue and green bands.