How to tell if tanzanite is real or not

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Named for its African country of origin, tanzanite is a blue stone used as a substitute for sapphire. Unlike the sapphire, tanzanites are a three-coloured gemstone. They contain three different shades of reds, purples, and blues that are visible to the naked eye.

Synthetic forsterite and blue-violet glass are both sold as tanzanite imitations. Besides inspection from a jeweller, there are steps you can take to determine the authenticity of your tanzanite.

Place stone on white surface. If the stone is mounted, place light below.

  • Named for its African country of origin, tanzanite is a blue stone used as a substitute for sapphire.

Hold filter around 36 cm (14 inches) from your eye, right over the stone.

Move filter from side to side, using the strip as a guide. View the stone from several different angles while moving the filter to ensure accurate results.

Compare colours seen with enclosed instruction chart. Imitation tanzanite such as fosterite will show a green colour through the filter. Authentic tanzanite will appear a pinkish-orange colour through the filter.

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