Natural Blue Tanzanite Faceted Roundel Beads Strand Length 12 Inches and Size 2mm to 5mm approx.Tanzanite is an extraordinary gemstone. It occurs in only one place worldwide. Its blue, surrounded by a fine hint of purple, is a wonderful colour. Tanzanite is trichroic and exhibits pronounced pleochroism. The colors respective to the three vibrational directions are sapphire-blue, sage green, and purple.