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Hey there. I'm new here and I work for the railroad. I recently spotted something rather unique. A string of about 4 poles with 2 purplish looking insulators. When I got them down they were stamped GTP tel co and GTP and when cleans up they were a lIght purple colour. any idea why the colour rather than just the standard green? Any idea what the value is?

Hi,welcome to the site! Its generally excepted that in the 1920s the insulator makers were experimenting with formulas to make clear glass for their customers. Some of their customers thought heavy colored glass sheltered bugs from heat and light.
One of the substances used that did result in clear glass was the addition of manganese in the glass mix.over time sunlight reacted with the manganese and turned the glass varying degrees of purple.
The large style of Beehive insulator used here in Canada marked G.T.P. or G.T.P. Tel Co. are fairly common in light purple.Depending on condition value is about $20-$30. The large Beehive marked T.C.R. in light purple is uncommon and valued at $200+.

Welcome to the site. Nice looking insulators, them GTP in light purple, not worth a huge amount, but a beautiful colour. Gerry, are you sure with the 20's timeframe? I thought most (if not all) glass manufacturers stopped adding manganese around 1913, since with a war looming, had better uses or couldn't get it. I'm not positive about all glass houses, but Dominion stopped adding manganese to their CROWN fruit jars around 1913, so if you find a real purple one, you know it predates 1913. I'd guess they did the same thing for their insulators.

Shawn

Hi Shawn! Thanks for keeping me honest on the time frame. I think its agreed that the canadian 145s were made in around 1910-15? .Mark Lauckners book" Canadian Railway Comunication Insulators 1880-1920" states that the 145 style was made from 1900-1930.The purple examples may date from the 1910 time frame possibly.
The last of the Canadian 145s would be the straw ,pink and peach No Embossing style which i think were manufactured much later. these pieces share the same color characteristics of the 154 Diamond style which were possibly made the same time.

These purples are sure pretty. They do come in a variety of shades though. There is a the steely blue purple looks purplish till you put it beside one that is light purple. Then there is the light purple these I agree are 20-30 then there is a strong light purple which I would not even consider selling for 30.00 as I have only ever found one in this colour I thought I had a picture of it somewhere but cant seem to find it.

Thanks for all the info. I'll see if I can't get some photos up!

Well Cndrbrown, are these beautiful enough to hook you like we've all been hooked? All it took was some commons and 1 dark purple to get me.

Shawn

Hey Craig!,Are those the G.T.P Tel Co. In a pinky purple like the 102 Diamond with the Number on the reverse?. I dont think most collectors have seen that piece. When Daryl Kling of Calgary dropped in for a visit and saw my pinky purple G.T.P. Tel co,s in the early 1990s he said he thought they were cooked!