Here is an historic add by the Chicago Insulating Company published in the 1880's promoting the products that they offered. The CD135 and CD109 styles were produced in glass and two nonglass styles were offered, the Knob insulator and an unknown Combination hook style. The Knob and Combination Hook styles examples have not been recovered and there are no known examples. The glass Fiske and Mott Patent insulators, are well known by the insulating collecting community and examples can occationally be offered for sale or trade. The insulator shown on the left side of the historic Add is the CD135 Diamond Groove, the insulator shown on the right side is the CD109 Teardrop Pony.
I started collecting the CD135's because I had always wanted one since I first saw one in 1969 on a pole in Denver, Colorado when I was a kid. It was many years before I finnaly was able to obtain my first example. Once I had it I realised that they were rather affordable and quite attractive with a style that was very unique. I feel the main drawback of Diamond Grooves is the lack of color varients.
In my collection I have some unusual examples as shown in the following pictures. I have identified 12 mold variations. Six of the base embossed types, and six shoulder embossed types of which three are the PAT. type and three are the PATd type.
Diamond grooves are found in colors that range in the above shown examples. They can frequently be found with milky streaks, amber streaks, pot stones, fire brick chunks, various size bubbles, and other bits of foriegn matter.
Here are examples in my collection that are filled with fizzy bubbles. The example on the left is a base embossed type and the example on the right is a PATd shoulder embossed type.