| Gemstone | Diagnostic Inclusions Shown | |----------|-----------------------------| | Diamond | Natural vs. synthetic growth features, black carbon spots, feathers, laser drill holes | | Corundum (Ruby/Sapphire) | Silk (rutile needles), boehmite tubes, fingerprint inclusions, color zoning | | Beryl (Emerald, Aquamarine) | Three-phase inclusions (solid, liquid, gas), mica plates, bamboo-like tubes | | Quartz (Amethyst, Citrine) | Negative crystals, hematite needles (e.g., in rutilated quartz), fluid inclusions | | Spinel | Octahedral negative crystals, partially dissolved zircons with halo fractures | | Garnet (various species) | Curved growth lines (in hydrothermal synthetics), apatite or zircon inclusions |