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Green Minerals: How to Tell Them Apart

Green is a useful search clue but a weak final identifier. Olivine, epidote, serpentine-group minerals, malachite, chlorite, and several altered minerals can all appear green. The host rock and texture often provide the fastest separation. Describe the shade precisely: pale, apple, olive, blue-green, or dark green. Check habit and setting: glassy grains in dark igneous rock suggest a different candidate than fibrous material in altered ultramafic rock. Test hardness on a fresh surface and note cleavage, splintery fracture, or flaky sheets. Use streak and a cautious acid test only when the specimen and field procedure make those tests appropriate. Surface staining by copper minerals or algae can colour an otherwise different material. Serpentine-group material may occur with fibrous minerals; avoid making dust and follow local asbestos precautions. Colour photographs shift with lighting and white balance, so compare the physical specimen when possible.