Topaz is a popular gemstone which can occur in a wide range of colours. Blue Topaz is often used in jewellery, which is usually a treated material using irradiation and heating of natural colourless Topaz.
TOPAZ, SKY BLUE
Hardness (Mohs’ Scale): 8 Specific Gravity (S.G.): 3.5-3.6 Refractive Index (R.I.): 1.61-1.64