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Red Minerals: Garnet, Hematite and Look-Alikes

Red is an attention-grabbing but non-diagnostic clue. Garnet, hematite, cuprite, cinnabar, realgar, and iron-stained minerals can overlap in photographs. Work from a clean observation surface, describe the shade precisely, and use non-destructive evidence before considering any test that could create dust. Describe whether the colour is deep red, scarlet, reddish brown, orange-red, or only a surface coating. Compare lustre and habit: glassy equant crystals, earthy masses, metallic grains, and resinous crystals suggest different groups. Check hardness and heft only on a stable, non-fibrous specimen using the least destructive suitable method. Record the host rock and associations, then compare streak only when the material is known to be safe to test. Iron-oxide staining can make quartz, feldspar, calcite, and weathered rock appear red without being a red mineral species. Cinnabar, realgar, and some other brightly coloured minerals contain hazardous elements; do not grind, streak, heat, or taste an unknown specimen. Garnet colour varies widely, so red colour alone cannot establish a garnet species or gem quality.