More on rock crystal from Fact Monster:

• quartz - quartz quartz, one of the commonest of all rock-forming minerals and one of the most important ...
• glass: Composition and Properties of Glass - Composition and Properties of Glass Most glass is a mixture of silica obtained from beds of fine ...
• Monte Albán - Monte Albán Monte Albán , ancient city, c.7 mi (11.3 km) from Oaxaca, SW Mexico, ...
• eyeglasses - eyeglasses eyeglasses or spectacles,instrument or device for aiding and correcting defective sight. ...
• silica - silica silica or silicon dioxide,chemical compound, SiO2. It is insoluble in water, slightly ...

See more Encyclopedia articles on: Mineralogy and Crystallography