A laboratory report can establish important facts about a gemstone, but it does not automatically tell you its quality, market value or whether you should buy it. This practical NGB guide explains each major section of a coloured-stone report and the limitations every gemstone buyer should understand.
A 10× loupe can reveal far more than inclusions. Learn a systematic gemstone examination workflow—from cleaning and surface inspection to darkfield microscopy, fibre-optic lighting, inclusion depth, fractures, growth structures and the limits of visual identification
Ruby and red spinel can look remarkably similar—and history repeatedly confused them. Follow a professional identification workflow using refractive index, optical character, specific gravity, fluorescence, spectroscopy and microscopy.
Three green stones. All are emerald. Only one formed naturally. Follow a professional evidence-based investigation using refractive index, specific gravity, dichroism, microscopy, growth structures and advanced laboratory analysis.
A colourless brilliant-cut stone arrives without documentation. Is it diamond, synthetic moissanite or cubic zirconia? Follow the evidence through magnification, optical properties, thermal testing and advanced laboratory screening.
Can you identify whether an unknown gemstone is natural, synthetic or an imitation? Work through a professional gemmological investigation step by step and learn why reliable identification comes from converging evidence—not one gemstone tester.
Four sapphires can share essentially the same RI, SG and optical character yet have radically different histories and values. Follow an advanced evidence-based workshop separating natural unheated, heated, synthetic and diffusion-treated sapphire.
An unknown green gemstone could be emerald, tourmaline, peridot, tsavorite or even glass. Follow a realistic evidence-based investigation using refractive index, birefringence, optical character, pleochroism, spectroscopy, specific gravity and microscopy.
Five blue gemstones can look deceptively similar. Work through a realistic gemmological investigation using refractive index, birefringence, polariscope, dichroscope, specific gravity, spectroscopy and microscopy to identify the unknown stone.
A red gemstone is placed on the gemmologist’s desk with no identification. Is it ruby, spinel, garnet or glass? Work through the evidence step by step using refractive index, optical character, spectroscopy, specific gravity and microscopy.
