The transparent, opaque or translucent base glass, talked about in the previous blogs, may be the first feature you see in a marble, but a marble’s color is often the feature that makes you want to pick it up and look at it. Identifying a marble by its color can be a challenge, but there are some striking differences between old marble glass and a new glass.
As with many things made back in the “good old days”, glass colors in older marbles are often richer and higher quality. The colors in “vintage glass” are also well defined. New marble colors, on the other hand, tend to be glassy, and watered down. Sometimes the new marble colors blend together.
Granted, new marble glass is often brighter. For example, the colors in JABO’s and Mega® Marbles are spectacular, but notice how they often appear oily. Some actually have a thin layer of clear glass on the outside. Many new marbles have an iridescent or pearl-like finish.
So where did these dynamic colors in old marbles come from? Glass is made from the simple ingredients of melted sand, soda ash, feldspar and other stabilizing ingredients. To give the neutral glass its color, chemical compounds are added in the furnace tank. For example, adding iron oxide in the glass mix creates a green marble, manganese creates a purple marble and adding cobalt pigment produces a blue marble.
When M. F. Christensen and Son, mentioned in an earlier blog, introduced the first marble machine, the company turned to the ancient craft of glass artistry and glass chemists such as James Harvey Leighton. Leighton, a third generation glass maker, has been described as the “Color Man”. He is credited with perfecting over 20 glass color formulas, including Oxblood, a sought after dark red colored glass that looks like dried blood.
Oxblood is found in many of M. F. Christensen’s early slag marbles. Look also for the brick red color in other early marbles, including Christensen Agate, Peltier Glass and Akro Agate. Leighton’s Oxblood formula was probably licensed to these companies.