Called ‘vitreous’ by the experts, the lustre of glass is gentle yet remarkable. The surface of glass has a smooth shine that reflects light gently; almost like water. This lustre gives glass bead jewellery a mildly sparkling look that is amplified under intense light. Glass takes on colour nicely. This is why glass beads are available in so many colours and in various degrees of intensity.
(quote from HMJS Jewelry)