What Is Fancy Square Glass?

Glass

• Although glass looks solid, it isn't. Matter exists in three states: gas, liquid and solid. Glass is actually suspended somewhere in between a liquid and a solid state. When silica sand, the primary ingredient in glass, is melted it becomes liquid. As it cools it becomes more and more solid, but never quite makes it to a solid state. According to an article by Robin Lloyd on MSNBC.com, this is because the molecules in glass are shaped like pentagons. Glass wants to crystallize as it cools, but its molecular structure physically can't fit into the orderly shape necessary for crystal formation. So glass molecules get stuck, or "jammed," on their way from liquid to solid. Look at an old pane of glass and you may see the effects of gravity causing the inside of the pane to sag or warp.

Making Glass

• Most glass is made from three ingredients: silica sand, soda ash and limestone. Silica sand melts and cools to become glass. Soda ash is what is called "flux"; it helps the sand melt at lower temperatures. Limestone is a "fixer"; it helps the glass retain its shape after cooling. These three ingredients are kept in powdered form in large silos. The powders are mixed, added to scrap glass to further facilitate melting and then loaded into the melting tanks. The tanks are then heated to between 2,600 degrees F and 2,900 degrees F in order to produce liquid glass. From the tanks, the molten glass is made into drinking glasses, bottles, windowpanes or a number of other items.

Color

• Glass gets its color from two sources. Either it is colored by impurities in the ingredients or somewhere in the production process or by an additive designed to produce a certain color or effect. Metals are often used to color glass. The addition of gold produces a red color, iron produces green hues, copper makes pale blues and tin produces white. Other additives include cobalt, manganese, lead antimony and sulfur. The various processes by which glass is colored create iridescence, swirls, stripes, splotches and even distinct patterns.

Techniques

• A few different techniques are used to create square vessels. Fusing and slumping are used to create small pieces, like bowls or plates. Pieces of glass are placed together in a desired pattern and then fired in a kiln to fuse them together. These fused pieces are then cooled, placed over a mold, such as a bowl, and then kiln fired again. This time, the flat piece melts, or slumps, downward into the mold, forming a bowl. Casting can also create square glass items, like sinks or table tops. Powdered glass or solid glass is laid into a mold in an artistic pattern. The mold is then fired, creating a fused piece of decorative glass. In mass production, molten glass is simply poured into a mold and allowed to cool.