Refractive index, specific gravity, inclusions, treatments and synthetics — the science a laboratory uses to identify a stone.
A synthetic ruby is real ruby; a simulant is not ruby at all. Why the terms matter, how a lab separates the three, and the disclosure you are owed.
The sequence a laboratory uses to identify a gemstone without harm — refractometer, specific gravity, microscope, polariscope, spectroscope and UV.
Many gems glow under UV. How the colour and strength of fluorescence help separate species, natural from synthetic and treated from untreated.
The spectroscope shows the dark lines where a stone absorbs light. Why those lines identify the colouring element, catch dye and expose cobalt glass.
Specific gravity is density against water. How a lab measures it by hydrostatic weighing, the SG of common gems, and why it is the key test for beads.
How a refractometer measures a gemstone's refractive index, the RI values of common gems and imitations, and why one number rules out most alternatives.
The polariscope tells single from double refraction; the dichroscope shows pleochroism. Two ten-second tests that eliminate whole families of imitations.
The Mohs scale ranks scratch resistance. Why labs almost never scratch a stone, what hardness actually proves, and hardness versus toughness.
Lab-grown diamond is diamond, so standard tests cannot separate it from mined. How HPHT and CVD growth work and the screening methods that do.
Most ruby and sapphire is heated. What heating changes, why it must be disclosed, the microscopic evidence a lab looks for, and the limits of detection.
Lead-glass filling turns fractured, near-worthless corundum into transparent 'ruby'. Why it changes value and durability, and how a lab detects it.
Burmese ruby, Kashmir sapphire, Colombian emerald: how origin is inferred from inclusions and chemistry, and why it is always an opinion.
Inclusions are the fingerprints inside a gem — the lab's main evidence for natural vs synthetic and for treatment. What the common ones look like.
Synthetic ruby, sapphire, emerald and quartz are grown by flame fusion, flux or hydrothermal methods. What each process leaves inside the crystal.
Nearly every emerald has fissures filled with oil or resin. What the fillers are, how minor-to-significant is graded, and how a lab detects them.
Diffusion cooks colour into pale corundum. Why surface-diffused colour is skin deep, how immersion reveals it, and the beryllium diffusion problem.
How thermal and electrical testers, doubling, dispersion and weight separate diamond from moissanite and cubic zirconia in minutes.
The four Cs work differently for coloured stones: colour dominates value, clarity is judged by species. How each is assessed and why grades are opinions.
The laboratory examines Rudraksha, gemstones, malas, bracelets and crystals and issues a numbered, PIN-protected report you can verify online at any time.