No one knows with certainty who made the Golden Guinea fountain pen but I would be prepared to make a small wager that it was a Mentmore product. It appears very similar to some other Mentmore and Platignum pens.
The name seems a little misleading. A guinea (21 shillings) was pricey for a pen in the thirties. For instance, the Conway Stewart Universal cost five shillings and sixpence in 1934* and it is a much higher quality pen than the Golden Guinea. I would guess that this inexpensive-looking pen cost a lot less than a guinea and the name was chosen to symbolise quality and worth.
Many of Mentmore’s inexpensive pens at this period were made from very attractive celluloids and it is the case with this pen. The white/grey/pink swirling pattern is very eye-catching and the black blind cap, clip screw and section provide a vivid contrast. The narrow/medium/narrow cap rings and the ball-ended clip have little more than a gold wash over the base metal.
The well-printed and strongly made box makes much of the “solid gold nib” but it is disproportionately small, another example of cost-saving. Taking the design as a whole, this low-cost pen with its pretty pattern was perhaps targeted at the school-pupil market.
The barrel’s tapering continues on into the section which is noticeably concave. The general shape is modern for the time, another attractive feature. Golden Guinea pens would make an interesting and attractive collection as during the couple of decades that they were around they picked up on the new and popular designs of those times, often in splendid patterns like this pen.
*Stephen Hull: Fountain Pens for the Million.