AI Appraisal Estimate

This is a pair of antique dodecagonal (12-sided) fluted glass doorknobs, featuring a distinctive light lavender or amethyst hue. This specific color is a hallmark of early 20th-century glass (typically 1880-1920) containing manganese, which turned purple over decades of exposure to ultraviolet sunlight. The knobs are mounted onto heavy bronze or brass collars with a dark, natural aged patina. These collars are secured to a threaded steel spindle using original slotted set screws. The glass is pressed and faceted to provide both a decorative geometric aesthetic and an ergonomic grip. Regarding condition, the glass shows minor internal striations and tiny bubbles consistent with early manufacturing processes, while the metal hardware exhibits a rich, even oxidation and minor surface wear from use. There appear to be no major chips or cracks in the glass, and the threading on the spindle remains intact, indicating the set is functional. The high quality of the glass molding and the density of the metal components suggest high-quality hardware craftsmanship from the late Victorian to Early Craftsman era.

Based on my visual examination of this fluted lavender glass doorknob set, I have assessed it as an authentic example of early 20th-century architectural hardware, likely manufactured between 1900 and 1915. The distinct amethyst tint is a diagnostic indicator of solarized manganese glass, a process that requires decades of UV exposure, making it difficult to replicate via modern chemical means. The 12-sided dodecagonal geometry and high-quality brass collars with deep oxidation suggest a premium product from a manufacturer like Reading Hardware or Yale & Towne. The glass clarity is excellent, with manufacturing striations that confirm period-correct pressing techniques rather than modern molded reproductions. In the current market, 'sun-purple' glass is highly sought after by restoration enthusiasts and collectors of Victoriana. The presence of the original threaded spindle and set screws adds significantly to the value, as it ensures functional utility. Current comparables for single knobs in this hue range from $60 to $90, while a complete, matched pair with hardware fetches a premium. However, authentication via digital image has limitations. I cannot verify the physical stability of the internal lead/sulfur settings that bond the glass to the metal collars, nor can I check for 'flea bites' or sharp chips along the facet edges hidden by the angle. A full authentication would require an in-person inspection to check for micro-cracking at the stress points and a UV light test to confirm the specific fluorescence of the manganese. Furthermore, provenance regarding the original structure it was salvaged from could increase the valuation for historical preservationists.