This is a 134 currently being auctioned on eBay. Here is the link:

https://www.eBay.com/itm/COBALT-BLUE-GLASS-INSULATOR-Patent-May-2-1893-Dec-19-1871-Nameless/352745233893

The pictures in the auction have a brown background, so it is difficult to tell the color. My first reaction was that it was irradiated, so I asked for better pictures. This picture (and the next) were provided to me by the seller.

There is no A on the dome, so the EIN that seems to be closest is [040]. But this one has no periods after the DEC and the 19 on the front skirt. So it arguably doesn't fit within any of the EIN's in the guide.

The closest listed color seems to be peacock blue.

Would anybody care to offer an opinion on the color? I'd appreciate any views on any aspect of this seemingly unusual piece.