Many Canadian insulators were made colourless at the factory by the addition of "decolourizing" agents in the glass. Colourless glass was viewed as superior in quality in the late 19th century and early 20th century, and it wasn't especially easy to make. In these early days of making glass colourless, it tended to change colour to something else when left outside and exposed to UV light for prolonged periods of time. UV light is strong enough to alter the chemical bonds in the glass when certain elements are used to change its colour, and that changes the way visible light refracts through the glass. This is perceived by us as the visible colour of the glass when we look at it. Glass is well known for having changed purple when exposed to UV light, but in some later years companies like Dominion used selenium to decolourize glass. Selenium glass changes to straw, pink, or peach shades when exposed to UV light for long periods of time, hence those colours being so common in Canadian insulators from about 1920 onwards.

It might be a stretch to say that once every few years I get the chance to view one of these pieces, and sometimes add it to my collection. I've been working on making a lineup of different styles for several years.

It's always difficult to photograph these things without picking up colours from the environment around, but here's a photo showing my modest collection of these pieces. They are as colourless as I've been able to find in these styles, and I've viewed many candidates in some cases. From left to right:

1.) A Dominion - 42 CD 154. While this may be the most common glass insulator in Canada, finding a truly colourless example is a very tall order. Many come close, but few are truly colourless. Dominion 42s can be found in a "nearly clear" shade that is a different mold variant with a taller skirt. That colour looks quite straw compared to this piece. This example also happens to have sharp drip points, which makes it all the more unusual.

2.) A 1678 CD 162.4 with round drip points. This represents the last generation of this style to be produced. This example is unfortunately not completely clear, but has a slight straw tint. Maybe it was exposed to UV for some short period of time through a window or something along those lines. It's as clear as I've found for a style that is generally only found in straw or peach.

3.) A Diamond CD 122. [id=750686560; I was able to add this one to my collection at this years 2025 Perth Ontario show]. It was once owned by Michel Brunet, a well-known collector from Quebec. Michel tells me this piece was found at an antique store within mere days of him developing an interest in collecting insulators, back in July of 2010. It's about as colourless as I've seen any Dominion products in, and it shows absolutely no signs of use - not even a wire scuff.

4.) A "modern variant" [165] Diamond CD 102. This piece came from the Lorne Temple collection. Lorne lived in Kanata - a suburb of Ottawa, Ontario - and was a staple at the Perth show for years. This is one of two identical pieces I'm aware of, but these late generation diamond ponies remain extremely rare in colourless glass like this.

5.) A B.T.C. MONTREAL CD 102. This is the only piece in my colourless Canadian collection that would turn purple if exposed to UV light. It's probably a full decade older than any of the others in this lineup. As with the others, it doesn't show any sign of use whatsoever. The vast majority of its mould twins are now dark royal purple shades, no doubt.

If anyone out there has other examples of these Canadian clear insulators I'd love to see them. I've seen a few that I don't have, and I'm always looking to add to my lineup as well. Please don't hesitate to get in touch!