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.
Gemstone identification is not based on one test. Learn how gemmologists progressively combine observation, microscopy, refractive index, optical character, pleochroism, spectroscopy and specific gravity—and when advanced laboratory testing becomes necessary.
Gemstone Specific gravity adds a non-optical measurement to gemstone identification. Learn how hydrostatic weighing works, calculate SG from weights in air and water, avoid common errors and combine density with refractive index and microscopy.
A handheld spectroscope reveals which wavelengths a coloured gemstone absorbs. Learn how to read absorption lines and bands, recognise characteristic chromium and iron patterns, compare prism and diffraction instruments and understand the limits of visual spectroscopy.
A dichroscope separates polarized colour components hidden inside anisotropic gemstones. Learn how to observe dichroism and trichroism in sapphire, ruby, tourmaline, iolite and tanzanite—and how pleochroism supports gemstone identification.
Learn how a gemstone polariscope uses crossed polarized light to distinguish singly refractive, doubly refractive and aggregate materials, detect strain and reveal uniaxial and biaxial optic figures
