The Christensen Agate Company was founded in 1925 in Payne, Ohio. In 1927, the company moved to Cambridge, Ohio, and was located in a small building near the Cambridge Glass Company. The company had no connection with Martin Christensen or the M. F. Christensen & Son Company. However, the original incorporators may have felt that the use of the Christensen name was a good marketing move.
The earliest Christensen Agate marbles appear to be hand-gathered swirls. These are very rare. Also, there have been boxes of dyed clays found that are Christensen Agate boxes with the Albright Company label pasted on top. It is unknown whether these clays were produced by Christensen Agate and then distributed by Albright, or if Albright simply used Christensen Agate boxes (Albright was a distributor of Christensen Agate glass marbles.
Christensen Agate produced slags in a variety of colors. These are transparent color base marbles with opaque white swirls in them. The pattern must be a transparent color base with opaque white. If the marble is two opaque colors, then it is considered a swirl. Also, the opaque white should be randomly swirled through the marble and the surface. If the white is banded or striped on the surface, with only a little inside, it is probably a striped transparent. Generally, the colors of Christensen Agate slags are much brighter than those produced by other manufacturers.
The most common Christensen Agate Company marbles are Swirls. Christensen Agate produced swirls in a great variety of different patterns and color combinations. The marbles were made by mixing two or more glass colors in a single furnace. Because each color was a different density, they did not melt together, but rather created strata. Since the molten glass was the consistency of molasses, the individual stratum remained as the glass was turned into marbles. There are an almost endless variety of colors and patterns in Christensen Agate swirls. The marbles can be two-color or multiple colors. There do not seem to be any swirls with more than five colors in them. Occasionally, the swirl patterns form a row, or two opposing rows, that look like the flames that were painted on the sides of hot rods during the 1950s. Marbles with these patterns are called Flames by collectors today and are rare. There are some swirls that have specialized names. Bloodies, which is the name used by the company, are an opaque white base with transparent red and translucent brown swirls. American Agates, again the name used by the company, are an opaque white to opalescent white base with a swirl that ranges from translucent electric red to transparent electric orange. Diaper-fold, a name applied by collectors today, refers to a swirl that is a single seam pattern. When viewed from the side, the swirl pattern looks like a diaper on a baby. Turkey, another name applied by collectors today, is a swirl pattern that looks like the head of a turkey.
Christensen Agate Company also produced a marble similar to the swirls. These were an opaque base with a series of color bands on the surface of one side of the marble, and little or no color on the other side or inside. Usually, the band colors are 'electric' and the base can be either opaque or transparent. These are referred to as Striped Opaques and Striped Transparents.
The 'World’s Best Guineas' are a transparent based marble with colored flecks of glass melted and stretched on the surface. Occasionally, you will see these flecks inside the marble, particularly in seamed examples. We have been told that the name Guinea originated because the marble colors looked like the heads of the Guinea Cocks that ran around the factory yard. The most common base color is clear, followed by cobalt and then amber. Some green based Guineas have surfaced, but these are very rare. It is rumored that a couple of red based Guineas that exist, but that cannot be documented. Cobras (sometimes called Cyclones) look like Guineas with all the stretched flecks of colored glass inside the marble. They have only been found in clear base and transparent blue. Rarest of all is a marble referred to as a Guinea-Cobra. This is a transparent clear base marble with Guinea flecks inside the marble, all on one side of the marble, and none on the outside.