Real vs Fake Pyrite: Pyrite vs Chalcopyrite & Painted Resin Tests

The Three Materials Most Often Confused With or Sold as Raw Pyrite

Real pyrite (FeS2) has three common impostors in the Indian crystal market: (1) Chalcopyrite (CuFeS2), a copper-iron sulfide sometimes called peacock ore for its vivid rainbow iridescence — beautiful, but not pyrite; (2) Painted resin or plaster clusters, factory-made with metallic gold spray paint, sold cheaply at tourist stalls; (3) Marcasite, a true polymorph of FeS2 with identical chemistry but orthorhombic crystal structure, indistinguishable without lab equipment.

Pyrite vs Chalcopyrite (Peacock Ore): How to Tell Them Apart

Chalcopyrite (CuFeS2) is a copper-iron sulfide that forms in massive or botryoidal habits rather than sharp cubic crystals. Its most distinctive feature is surface iridescence — under light it displays blues, purples, pinks, greens, and golds simultaneously (hence 'peacock ore'). Real pyrite does not do this. Pyrite's surface is uniformly pale brass-gold to silver-gold, with no colour play.

Hardness is the definitive field test: chalcopyrite is 3.5-4 on the Mohs scale, which means a copper coin (hardness ~3.5) will scratch it. Real pyrite at 6-6.5 cannot be scratched by a copper coin, a steel knife, or even a steel file. Run the coin firmly across an inconspicuous edge and inspect under good light.

How to Detect Painted Resin or Plaster Fake Pyrite Clusters

Painted resin and plaster fakes are common in tourist markets and low-price online listings. They are made by pouring resin or plaster into a mould, allowing it to set in a rough cluster shape, then spray-painting with metallic gold paint. The result can look convincing in photographs but fails every physical test.

1. 1
   Scratch with copper coin

   A copper coin (hardness 3.5) scratches resin/plaster instantly. Real pyrite at 6-6.5 shows no mark.

2. 2
   Hold under light at an angle

   Real pyrite has distinct flat cubic faces with sharp edges. Resin fakes show rounded, blob-like bumps with no geometric regularity.

3. 3
   Feel the temperature

   Mineral pyrite feels cold to the touch. Resin and plastic warm up in your hand quickly.

4. 4
   Check the weight

   Pyrite has specific gravity ~5 — it feels surprisingly heavy for its size. Resin/plaster fakes feel noticeably light or hollow.

5. 5
   Look at the base edge

   Where the base of the cluster was in the mould, resin fakes often show a flat mould-line and paint peeling at edges.

6. 6
   Price check

   If a 'pyrite cluster' is priced under Rs 100-150 for a fist-sized specimen, it is almost certainly resin. Real pyrite of that size costs Rs 300 minimum from any honest source.

Pyrite vs Marcasite: The Polymorph Problem

Marcasite is a true polymorph of pyrite — identical chemical formula (FeS2) but a different crystal structure (orthorhombic rather than isometric/cubic). It has similar lustre and colour to pyrite. Marcasite is less stable, oxidises even faster than pyrite, and has a tendency to crumble over time. Telling them apart requires X-ray diffraction (XRD) or precise specific gravity measurement.

For practical purposes: if a specimen has clear cubic crystal habit (sharp flat faces in cube or pyritohedron form), it is almost certainly pyrite, not marcasite. Marcasite tends to form radiating, spear-shaped, or cockscomb habits. If you are buying an investment-grade specimen, request lab verification specifically confirming isometric crystal system (pyrite), not orthorhombic (marcasite).

Five Field Tests You Can Do Before You Buy

1. 1
   Crystal habit (visual)

   Look for sharp, flat cubic or pyritohedral faces with geometric regularity. No cubic faces = suspect chalcopyrite or resin.

2. 2
   Colour uniformity

   Real pyrite is uniform pale brass-gold. Rainbow/iridescent = chalcopyrite. Overly perfect bright gold = painted.

3. 3
   Copper coin scratch test

   Press a copper coin firmly on an edge. Scratches easily = resin or chalcopyrite. No mark = likely real pyrite.

4. 4
   Heft test

   Real pyrite feels heavy for its size (SG ~5). Light or hollow feel = resin.

5. 5
   Temperature test

   Hold for 10 seconds. Still cold = mineral. Warms up = resin/plastic.

Pyrite vs Chalcopyrite vs Gold Quartz vs Resin: At a Glance