How Crystal Glass Is Made

Ingredients

Crystal is more commonly perceived as glass. The inclusion of 24 percent or more of lead oxide is what makes crystal what it is. The glass is composed of three ingredients. One is sand (silica). When the silica is heated to extreme intensities, the sand forms into a fragile state of glass. Soda ash (sodium carbonate) is a white, powdery material that is added to prevent the melting temperature of the sand. Last is limestone (calcium carbonate). This helps to make the glass firmer and stronger. When the lead oxide is introduced to the glass, it adds the brilliance and weight. The lead also makes the glass more malleable for cutting.

Manufacturing

The ingredients for the crystal are mixed and heated at temperatures that can reach 3,600 degrees Fahrenheit. The lead oxide will then be placed into the furnace. The amount of lead introduced enhances the beauty of the product. Most crystal items will not contain less than 30 percent lead.

The Process

While crystal is blown glass, it is necessary for four or more people to work with it due to its weight. The crystal begins as nothing more than a ball of molten glass. The workers are placed in groups around a furnace. They remove the ball from the furnace on an end of a blow-iron.

Glass Working

A glass worker will blow through a tube to form a hollow sphere. This steel tube is 4 feet long and is continually rotated. Molds are used to create a shape. Once the molten glass touches the mold, it will begin to cool rapidly. The workers must move quickly to form the crystal.

Shaping and Annealing

Once the desired shape of the crystal has been achieved, it is taken to what is known as an annealing oven. The annealing oven is a long chamber where the crystal will go through variant temperatures. The process keeps the crystal from shattering, since it is necessary to prevent it from cooling to soon. The process can take as little as 2 or as long as 16 hours.

Cutting

Once the annealing process is complete, the crystal is now ready to be cut. This is an important process. A pattern is drawn on the crystal, and the design is roughly etched. The crystal is then held against the edge of a cutting wheel to refine the design. There are two basic cuts: wedge cuts and flat cuts. Wedge cuts produce the deeper facets, and flat cuts create contrasting cuts.

Polishing

Once the crystal has been cut, it is placed into a mixture of hydrofluoric and sulfuric acid. The crystal is then rinsed, and transforms into a sparkling piece of art.

Resources

• Crystal Art
• Crystal Making