Hello Bill, thanks for your response; I respect your opinion very much. I do not think these gear companies intentionally lie. But they do make mistakes. I think they changed over to sil-nylon for the latest production runs of the ion and didn't update their web page. A comparably serious error was recently made by Helly Hansen and thier "59gram" Zone jacket.. The retailers picked up on that manufacturer's data and quoted it. That was not a Marmot product, but serves as an example.
You are correct, I am not qualified by any educational institution to test fabric, but comparing it side by side with Pertex and sil-nylon, it is similar to the sil-nylon in texture, coating, breathability(lack thereof), and 'hand'. This is not just my WAG; other posters who bought the jacket recently had the similar observations.
Quotes from a couple sources who know more than me:
1. Pertex "..allow a precisely controlled amount of airflow through the fabric." -www.pertex.com
The Ions I'm holding have 0 air permeability.
2. Richard Nisley seems to know much more than I do. He suggests the following tests:
– You can identify it [Pertex Quantum] by noting how easy it is to breathe through compared to other fabrics. [Ion fails, can not breathe through it at all; "real" Pertex Snugpak bag as my 'control' passes]
– You can put an LED light under it and you should be able to see the pore pattern on top. [Ion fails, has no pores, it looks just like sil-coated ripstop nylon; Pertex 'control' passes]
– You can put a magnifier over the fabric and look for its distinctive large obviously visible pores. [Ion fails, Snugpak 'control' passes]
Marmot has a 1800 number, but no email contact I can find so I'll call to see what they say, for the benefit of the others who bought this jacket.
Im not trying to be argumentative with anyone here, nor with Marmot; I just want truth in advertising since I buy most of my gear sight-unseen over the internet!