... ~1.20, about half of glass.2. Superb optical clarity with crystal gloss, with light transmission of 93% (for clear sheet), higher even ... than glass.3. Excellent light diffusion, which allows opal sheets with varied light transmission rate to ideally suitable in lighting and ... or press when heated up to 145~155 Celsius degree with circulating oven.6. Good surface hardness, close to aluminum, and ...