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
A gemstone refractometer converts gemstone optics into measurable evidence. Learn how to take accurate refractive-index readings, recognise single and double refraction, calculate birefringence, use spot readings and understand when RI alone is not enough
A gemmological microscope reveals far more than magnification alone. Learn how darkfield, brightfield, fibre-optic, reflected and polarized illumination expose inclusions, colour zoning, treatments, surface features and growth structures.
A 10× loupe is one of gemmology’s simplest and most useful instruments—but only when used correctly. Learn how to use a 10x loupe with professional focusing technique, lighting, systematic gemstone inspection, what inclusions can reveal, and when magnification alone is not enough
