What is precious resin?

You may have seen companies like Montblanc and Faber-Castell claim that their pens are made of “precious resin”. But what exactly is “precious resin”?

tl;dr It’s plastic. For more details, read on.

Why “precious” resin?

“Precious resin” as used to describe a material for fountain pens is an unfortunate odd translation of the German word Edelharz. This does literally translate to “precious resin”, however, in this context, Edel means long-lasting, non-degrading, or specially formulated. (Compare with Edelstein precious stone / gemstone, or Edelstahl stainless steel.)

The term Edelharz has its origin in the pen wars of the 1920s where at the time a lot of pens were made of various materials like celluloid that were prone to deterioration. The name Edelharz was meant to signify that the new material was sturdier, more resistant to drops, and longer-lasting than competitors’ materials. A more accurate translation might be “high-grade resin”.

What is the material exactly?

It is a plastic resin called poly(methyl methacrylate) or PMMA, sometimes known under the genericized brand name plexiglas. Often the term “acrylic” is used to describe this material, but acrylic can also include other acrylonitrile-based polymers.

PMMA is one of the most commonly used pen materials; companies making pens with PMMA include Sailor, Pilot, Faber-Castell, Montblanc, as well as many small independent pen makers.

Is it just to make it sound fancier?

Not originally—it was just an awkward translation into English. However, since Montblanc was acquired by Richemont, a luxuries company, Montblanc has played up the idea of “precious resin” and featured it prominently in its marketing as if it were something special, while being very careful to not describe exactly what it is. So, these days, it’s at least partially a marketing thing.

However, other companies also use this term for their acrylic material, and they do not use it prominently in their marketing, but rather refer it as a side note in their technical specs. So it’s not always for marketing; sometimes it’s just a name for the material.

Is precious resin turned rather than injection-molded?

Despite a popular misconception, this is not what makes resin “precious”. Most mass-produced pens made of acrylic are injection-molded, including relatively expensive ones such as Montblanc 149, Sailor Pro Gear, or the Pilot Custom series. Generally, it is the smaller pen makers using resin blanks and making turned pens, but these tend to be advertised as “acrylic”, not “precious resin”.

Is precious resin stronger than other plastics?

There’s no standard definition of what precious resin is, so it’s hard to say. But acrylics do vary in their characteristics based on the process used to make them as well as the exact formula of acrylic that is used. There is at least good anecdotal evidence that Montblanc’s pens are quite drop-resistant and that their claim of quality is real, though there are the occasional models of Montblanc that have been known to crack easily.

Cheaper pens made of acrylic are often not as sturdy as their more expensive counterparts, likely due to shortcuts taken during manufacturing. After injection molding, the cooling process and temperature must be carefully monitored, otherwise this can introduce imperfections that may cause the material to be crack-prone. This is often one of the first corners cut when reducing manufacturing costs, so some pens, despite using a proven material such as PMMA, have issues with cracking. This generally affects the lowest price tier the most (2–5 USD), but more expensive pens can occasionally also fail due to manufacturing defects; this is quite rare, but known to happen with Sailors, for example.

In conclusion: precious resin is plastic.

At the time of its introduction, it was a new, more sturdy plastic, and that’s why it got its precious name. But nowadays, pens using PMMA are commonplace, so it's hardly precious anymore.