How to tell if tanzanite is real or not

Written by karla h
  • Share
  • Tweet
  • Share
  • Pin
  • Email
How to tell if tanzanite is real or not
Tanzanite is used in a numerous types of jewelry. (Getty Images)

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.

Skill level:


  1. 1

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

  2. 2

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

  3. 3

    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.

  4. 4

    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.

Tips and warnings

  • There are test kits that include both a filter and dichroscope, many also have a detailed chart with colour descriptions.
  • Filters may also be called "Hanneman" filter.
  • Using fluorescent or sunlight will cause incorrect readings with a filter.
  • Stones that have been set with a dark solid backing may be harder to test using a dichroscope or filter.

Don't Miss

  • All types
  • Articles
  • Slideshows
  • Videos
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the site, you consent to the use of cookies. For more information, please see our Cookie policy.