Gemstone Identification Tool

Start with the four properties you can observe without lab equipment: colour, approximate hardness (whether it scratches glass or is scratched by steel), transparency (transparent, translucent or opaque) and lustre (how it reflects light). Enter those into the tool above and it ranks the gems that best fit. For a definitive ID, a gemmologist measures refractive index and specific gravity.

The Mohs scale ranks mineral hardness from 1 (talc) to 10 (diamond). A simple test: ordinary glass is about 5.5 and a steel knife about 6.5. If your stone scratches glass it is harder than 5.5; if a knife scratches the stone it is softer than 6.5. Do any test on an inconspicuous spot, as it can leave marks.

Yes — many gems share a colour. Red could be ruby, garnet, spinel or red tourmaline; clear stones could be diamond, white sapphire, zircon or quartz. That is why combining colour with hardness, transparency and lustre dramatically narrows the options, which is exactly what this tool does.

It suggests what your stone is most likely to be based on observable traits, but it cannot confirm authenticity, detect treatments, or appraise value. Lab-created and imitation stones can mimic naturals closely. For anything potentially valuable, have it tested and certified by a professional gemmological laboratory.

Many of the gems this tool identifies are also birthstones — garnet (January), amethyst (February), aquamarine (March), diamond (April), emerald (May), pearl & alexandrite (June), ruby (July), peridot (August), sapphire (September), opal & tourmaline (October), topaz & citrine (November) and turquoise & tanzanite (December). Matched gems link to their birth-month guide.