Where's the Iridium?

"There is no iridium in the iridium", Kurt Montgomery said to me as we looked over the print out from the EDAX. We were looking at the material analysis of a Waterman's Green #7 nib tip from the 1930's.

Most pens today (and in the past) use an alloy of materials for the hard surface tipping on the end of the nib. This alloy is composed of a number of elements. If iridium is present at all, it is rarely the predominate element.

The word iridium has become synonymous with tipping, in much the same way that Kleenex is synonymous with tissue paper. We all know what we mean when we say iridium. It is the little bit of hard white metal that is attached to the gold points of a fountain pen.

My first inkling of the relative absence of iridium occurred in 1991 when I took in a piece of tipping from a 1918 Waterman's N.Y. Ideal #2 nib to the Pacific Spectrographic Laboratory in Los Angeles for analysis. I got to watch as they put my pinhead sized piece of metal in a ten-foot long machine. Using a burst of energy, they vaporized the sample, turning in into a tiny cloud inside a chamber. They then read a spectrum of light as it passed through the gasses. The results* were:

  • Iridium - 54%,
  • Osmium - 44%,
  • Silver - 0.70%, (these three last very small parts of the alloy were probably contamination from the gold nib or the solder used to fuse the tip to the gold.
  • Copper - 0.50%,
  • Gold - 0.24%,

with possible traces of Ruthenium.

I have learned, by examining the margin between the tipping and the gold of the nib, that all early points, those made before the 1940's were made by attaching rough chunks of unshaped tipping to the end of the nib. I could see a rough margin between the materials, which indicated the crudeness of the material that was placed on the end. This margin can be seen using a 10-power loupe. In the early days of nib making, the material used was unrefined ore, crushed to size and applied onto the tip of the un-slit nib. It is for this reason that there was a fair amount of difference in the tipping material, depending on where on the earth it came from.

Melting and alloying tipping material posed insurmountable problems for the earliest pen makers. For this reason, many of the earlier tips exhibit flaws that can be seen running from one side of the points through to the opposite tine tip. A fine uniform material was just not available.

An analysis of naturally occurring iridium ore shows iridium in the presence of osmium and ruthenium. (1)

One very prominent theory has it that these materials are from asteroids that have fallen to earth. The iridium that was present on the earth, when the earth was formed, had dropped to the molten center, leaving very little iridium on the surface. [(This hypothesis explains the death of the dinosaurs and most vegetation of the time as a catastrophic occurrence, the impact of a huge asteroid off the Yucatan Peninsula, on the East coast of Mexico, during the Cretaceous Tertiary (nicknamed the K-T event.)] As the theory goes, not only did this event kick up so much dust and debris that it blotted out the sun for years, but it also deposited a thin layer of soil all around the globe with higher than expected iridium content. This soil layer has been found in Italy and other distant places on the globe. (2)

Last year, while making electron microscope photos of contemporary Parker Duofold nibs with Kurt Montgomery, he explained that a material analysis was also possible with EDS, energy dispersive spectroscopy. By directing a beam of electrons at the metal, the composition of the material could be analyzed.

The earliest Parker nib tipping that we looked at was a Lucky curve (lazy "S") from the mid-teens. Its analysis* shows similarities to that of the first one that I analyzed, the Waterman's from about the same period, except that this time there was more osmium than iridium:

  • Osmium - 44.3%
  • Iridium - 34.8%
  • Ruthenium - 20%

We looked at a 1920's Parker Duofold Sr. and found that the material was from different metal groups, a sure indication of an engineered alloy. Notice that when the iridium disappears, the tungsten shows up. This tip still shows the rough margins indicative of fractured tipping material, not the uniform pellets that came in during the next decade.

  • Osmium- 85.3%
  • Platinum - 5.9%
  • Tungsten - 4.51%
  • Ruthenium - 2.01%
  • Copper - 1.84%

A second 1920's Duofold revealed the following different engineered tipping composition. Tantalum is very resistant to acid attack, so it could be in there to hold up against the ink.:

  • Rhodium - 43.6%
  • Ruthenium - 19.3%
  • Gold - 17.4%
  • Osmium - 6.9%
  • Tantalum - 6.8%
  • Copper - 5.3%
  • Iron - 0.7%

(It is possible that in this sample, the machine read some of the gold nib material, which showed up as gold and copper.) But even so, when factoring this out, the other materials still had a very different composition from the other Duofold that we looked at. Where was the iridium? Parker Duofold nibs of the 1920's were the gold standard of fine tips. I draw two conclusions from this analysis: Parker was still experimenting with their alloy, and iridium was not a necessary ingredient.

We can date the senior Duofold size Lucky Curve nib fairly accurately to the period when Parker first came out with the Jade Plastic pen around 1924. Its composition shows no iridium at all:

  • Osmium - 96.6%
  • Rhodium - 3.4%

A later Duofold pen, with the "Made in USA" imprint from around 1929 shows a very different makeup. We are back to the platinum group of metals characteristic of earlier "as found" material tips:

  • Osmium - 38.4%
  • Iridium - 32.3%
  • Ruthenium - 29.0%

A #4 New York Waterman's tipping, ca. 1920 is similar to the Parker Lucky Curve pen of a time almost ten years later. This is more of the naturally occurring "iridium":

  • Osmium - 34.6%
  • Ruthenium - 33.4%
  • Iridium - 30.0%
  • Iron - 2.0%

A Parker Vacumatic from the late 30's shows the first major appearance of tungsten along with cobalt. Here again Parker is engineering different alloys.

  • Ruthenium - 32.3%
  • Osmium - 29.6%
  • Tungsten - 20.1%
  • Cobalt - 18.1%

A 1940's Duofold shows a heavy reliance on tungsten. Because it does not occur in nature with the Platinum group this is a designed material tip (3):

  • Osmium - 58.2%
  • Tungsten - 41.8%

Tipping on the Parker 51 with its nib marked RU is applied as a pellet. Because pelletized metal do not occurs in nature, we can surmise that this was refined, alloyed, and turned into a form that could easily be used in manufacturing. (An awareness of osmium as a dangerous biologically reactive substance occurred around this time and may explain its absence. Osmium oxide’s toxicity was well documented by 1940.)

  • Ruthenium - 96.2%
  • Iridium - 3.8%

We already saw Waterman's material from the teens and 20's and how similar it was to that used by Parker. Now in the 30's a similar pattern of material usage emerged.

A Waterman's #7 Green nib from around the mid 1930's looks like an intentionally designed alloy:

  • Osmium - 70.4%
  • Tungsten - 13.6%
  • Platinum - 10.3%
  • Aluminum - 4.0%
  • Nickel - 1.7%

A Conklin from the 1930's with a crescent breather hole looks to be, with its mix of metal types, a crafted alloy as well:

  • Osmium - 47.9%
  • Ruthenium - 33.9%
  • Tungsten - 16.0%
  • Iron - 2.6%
  • Nickel - 1.6%

Sheaffer's nib tipping, from as far back as we could find samples, presented the greatest number of components; a total of seven in the early, circa 1919 Sheaffer's self-filling #4. Tungsten, though neither precious nor noble, is very hard and durable. Sheaffer's company, based on our findings, was the first to engineer their tipping alloy:

  • Tungsten - 45.6%
  • Nickel - 33.4%
  • Iridium - 7.7%
  • Osmium - 4.7%
  • Iron - 4.6%
  • Silver - 4.5%
  • Aluminum - 2.5%

The large Sheaffer's Lifetime from the mid 1920's shows a very different profile:

  • Rhodium - 55.0%
  • Osmium - 31.8%
  • Ruthenium - 8.2%
  • Platinum - 3.0%
  • Aluminum - 1.7%
  • Iron - .3%

The Sheaffer's Feather-Touch from the late 1930's with both tungsten and cobalt is most similar to the Parker Vacumatic from around the same period:

  • Ruthenium - 37.1%
  • Osmium - 30.2%
  • Tungsten - 22.2%
  • Cobalt - 8.2%
  • Aluminum - 2.0%
  • Iron - .5%

The presence of aluminum, iron and copper, I believe, may be looked at as a sign that the metallurgists were not entirely in control of the materials that they were putting into the alloys. These materials are either not hard, easily corrode, or both. The other materials in these alloys are workable tipping materials. Or possibly, Sheaffer's was experimenting with small amounts of these elements to some end that I do not understand. Sheaffer's company was well ahead of their time in many of their products and processes. (Consider the early use of plastics and the perfection of the lever filler.)


I am certain that tipping was used in some sort of raw form on the earliest nibs. I have come to believe that sometime around the late teens, metallurgists were able to refine the ores and alloy them into more desirable and/or less expensive metals. It seems that a great deal of experimentation was going on during this period in order to find a superior material. And finally, the modern era of tipping emerged with the pelletized tipping, which I have first seen on the Parker 51. All gold nibs made today use regular spherical forms to provide the wearing hard surface. A future article will look into the materials of contemporary tipping. (Of the few that I have looked at so far, none contain iridium)

*Please note that because of averaging, or because only the elements that we were looking for, show up, the numbers often do not add up to 100%.

(1) Iridosmine (or iridosmium or osmiridium) is a naturally occurring alloy.

It contains osmium, iridium and smaller amounts of Pt, Ru, and Rh.

The ratios in references are quite varied, one is 17-48% Os, 48% Ir, and Pt, Ru and Rh (ca. 1974). Others current sources list it at up to 80% Os and up to 77% Ir. A 1932 Russian technical paper (where the pen tips were probably from) states osmium contents between 30 and 65 weight %.

O. E. Zvyagintsev, Z. Krist., 83, 1932, 172-186

(2) "In 1980 Alverez, Alverez, Asaro, and Michel, reported their discovery that the peculiar sedimentary clay layer that was laid down at the time of the extinction showed an enourmous amount of iridium. First seen in the layer near Gubbio, Italy, the same enhancement was seen worldwide in a 1 cm layer both on land and at sea. The Alverez team suggested that the enhancement was the product of a huge asteroid impact. "On Earth most of the iridium and a number of other rare elements such as platinum, osmium, ruthenium, rhodium, and palladium are believed to have been carried down into Earth's core, along with much of the iron, when Earth was largely molten. Primitive "chondritic" meteorites (and presumably their asteroidial parents) still have the primordial solar system abundances of these elements. A chondritic asteroid 10 km (6 mi.) in diameter would contain enough iridium to account for the worldwide clay layer enhancement.

This enhancement appears to hold for the other elements mentioned as well. "http://spacelink.nasa.gov/Instructional.Materials/Curriculum.Support/Spa...


(3) "The Platinum Metals and Their Alloys" by R. F. Vines,

The International Nickel Company, Inc, 1941, NY, NY. Kurt Montgomery pointed this reference out to me. He said, "This is an interesting reference since it is contemporary with some of the nibs analyzed. In the 1941chapter on iridium, there is no mention of using pure iridium as a pen tipping material, either currently or previously." (pg. 43-45.)

Many thanks to Kurt Montgomery, without whose help this article would not have been possible.

Publish Date: 
Sunday, August 3, 1997

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