Glass is made from silica and other materials. It is not affected by the weather nor by most chemicals. Most glassware is easily broken by blows; sometimes hitting it hard only damages the glass invisibly so that later it shatters from just a light impact. Glass is blown or molded into many shapes for decorative items, and for beverage glasses and other eating and serving dishes.
Crystal is made from the same basic material as glass but lead is added to fine crystal which adds sparkle and strength.
Heat-resistant glassware has been treated to withstand high temperatures. Such utensils may break when subjected to sudden changes in temperature. Ovenware is not suitable for top-of-range use as it is not made to stand direct flame heat.
Glass ceramics are made from hard crystalline materials which were first used on missile nose cones. Glass ceramics are used for range tops, counter tops, dinnerware, and cookware. The cookware may be used in the oven, under the broiler, on the stove, or in the microwave oven. They are guaranteed by the manufacturer not to break from temperature change.
This article was written by Anne Field, Extension Specialist, Emeritus.