is a substance whose form is dependent upon a great number of properties. It can be categorized under different types. Soda-lime is theleast expensive of the types for good reason. Lead is used most commonly as an art . Borosilicate has many advantageous properties. Aluminum silicate is not quite so common. Ninety-six percent silica is the result of the removal of almost all of the non-silicate components in silica . Fused silica is the most expensive and the hardest to fabricate. is an amorphous substan ....