18 x 49 ironing board cover_blue plastic table cover

(8) With hair inspection: Put the crystal on a hair, the human eye can see the double shadow of the hair through the crystal, it is natural crystal, mainly because the crystal has birefringence.

1. Melting The process begins with melting raw materials, primarily silica, soda ash, and limestone, in a furnace at around 1,700 degrees Celsius.