Antique Olive Green Glass Electrical Insulator with Diamond Mark

This item is an antique glass electrical insulator, likely dating from the early 20th century, possibly between the 1900s and 1930s given the style and material. It is distinctly colored in a dark olive green or almost black-green hue, with some areas appearing lighter green where light passes through, particularly at the base. The insulator has a classic 'spool' or 'thread' type shape, with a domed top and a series of concentric rings or grooves visible on the upper, round portion, suggesting it was designed to help shed water. Below the domed top, there is a prominent concave band or groove that transitions into a wider, tapering skirt. The overall construction appears robust, typical of utilitarian electrical components of its era. A distinguishing feature is a raised, diamond-shaped marking on the lower, wider skirt of the insulator. This mark is clear and well-defined, suggesting it might be a manufacturer's mark or mold number. The surface shows evidence of age and use, including some minor surface irregularities and what appears to be dirt accumulation or patina, particularly in the grooves. There are no obvious cracks, chips, or significant damage visible, indicating a relatively good state of preservation for its age. The glass exhibits subtle variations in thickness and texture, characteristic of older manufacturing processes. The craftsmanship reflects typical industrial production of the period, prioritizing function and durability.