The Onyx trumpet was produced at the Olds plant from c.1974-1976, replacing the solid nickel-silver Argenta model in the catalog. Onyx models featured a deep black lacquer [aka “black nickel”] finish over nickel-plated brass areas of the horn; the dark ebony contrasted with the polished nickel silver used on the tuning slides and trim areas.
A significant number of Onyx models have been seen without the distinctive black finish – instead showing what appears to be brass underneath where, based on the catalog descriptions, it should be nickel plating. It’s unknown just how durable the Onyx finish was and/or what the actual materials were for this model.
1974 Reynolds catalog:
The Onyx TU-20 is an exceptional professional trumpet in appearance, design and performance. Precision engineering and quality craftsmanship provide excellent intonation and powerful projection and the smooth, silent valve pistons insure a fast, fully responsive action. The first valve thumb hook offers more precise control over intonation. A slightly darker, more centered tone is achieved thanks to the Onyx finish. The contrasting nickel silver outer tubes and trim complement this instrument, and give it a unique, handsome appearance. Deluxe instrument case and accessories are included.