Authentic Dzi, or Gzi beads, are said to have medicinal powers. They are used in Tibet to cure illnesses ranging from high blood pressure to heart disease. Collectors of Dzi beads have to be on the lookout for fake beads, which are sometimes marketed as Middle Age Dzi Beads or Antique Dzi Beads instead of Ancient Dzi Beads. Distinguishing the authentic beads from fake beads involves seeing the beads in person, as you must be able to touch the beads and view them under magnification.
Check the cost. Fake Dzi beads will cost significantly less than authentic beads. Authentic beads usually cost over £65, and possibly more than £650 per bead.
Look for cinnabar dots or blood spots. These are red dots on the Dzi bead that are formed from inside of the rock. In some cases, newer authentic Dzi beads may not have these dots.
Notice the sheen on the beads. During the natural weatherization process, an oil-like sheen is formed on the beads. There should be variations in the way light is reflected on the beads, as it isn't likely that the entire bead will weatherize exactly the same.
Be on the lookout for medicinal digs in the beads. An authentic Dzi bead will have small chips where the Tibetans dug into the bead for medicinal purposes. Fake Dzi makers usually don't take the time to recreate these marks.
Inspect weathering marks. In fake Dzi beads, the weathering marks will seem uniform and the edges of the marks will be sharp. In authentic Dzi beads, the weathering marks will be uneven and the edges will be smoothed down from the weatherization process. A magnifying glass or jeweller's glass is needed to fully inspect the marks.
Keep an eye out for crystal in the bead or for streaks in the bead. New Dzi beads and fake Dzi beads won't have any crystal in the bead and most won't have natural looking streaks in the beads.
Run your finger along the holes at the end of the bead. Authentic Dzi beads usually have a slightly rough texture around the holes. Fake beads are usually completely smooth.