Hey, kids!  Are you ready for some science? Of course you are!  So, on the topic of the Fabric Mart “silk” versus the Denver Fabrics “acetate,” it’s time for a little experiment. After getting lots of helpful tips from readers and reading a bunch of web pages about burn testing fibers (not terribly consistent, by the way), I went to my local pharmacy after work and picked up some nail polish remover with acetone to see whether the fabric would dissolve in it, thus indicating acetate.

After my initial burn test I was fairly convinced that whatever the fabrics are, they are the same.  Even so, I decided it would only be fair to test both of them. So I took a scrap of each and some glass yogurt jars, figuring that would be nice and non-reactive (I save them for when I make jam or pickles – useful and conveniently sized!) and here’s my experimental setup:

I then poured in a little bit of Cutex “Strengthening” Formula, enough to cover:

I kind of figured that if this fabric were acetate, there would be a rather immediate shriveling reaction, sort of like when you pour water on the Selfish Seamstress.  But nothing happened.  I swirled it around a bit.  About fifteen minutes later, both swatches were still intact:

So. It’s been about a half hour now, and there’s little change except that it seems like maybe some of the blue dye has run off into the nail polish remover. Other than that, the fabric is holding up.

On the basis of this test, as well as the fact that the burn behavior of the swatch (crispy nubbins of black char on the burning edge, no obvious melting, self-extinguishing) was similar to my known-to-be-silk dupioni scrap (the dupioni feels, crumples, and smells like silk), I’m going to call this one in favor of Fabric Mart and declare both fabrics to be silk. I’ve already ruled out rayon, and I assume polyester and nylon would melt. Yay for science and observable phenomena!

Now, a little bit of sleuthing, as I think we were all a little bit skeptical and perhaps still are.  How could Denver Fabrics possibly have listed a silk fabric as acetate, sold it at $3.75/yard, ad then put it on sale for $1.99/yard? Well, if you look at the fabric description, you’ll see there is another error:

The fabric is described as “jacquard,” which would suggest a pattern woven in different textures. This is incorrect- the fabric I received is definitely twill, with a consistent diagonal weave, and the design printed on.  So what happened? A little poking around on Denver Fabrics’s website turns up several other “100% acetate” linings that have this pattern rendered in a single color at a 49″ width, such as this navy one:

Close inspection of the image suggests that this one actually *is* a jacquard in a solid color, and that the clover pattern is woven in (satin weave clovers on a matte ground, reversed on the other side), rather than printed as it is on my fabric. This lining is also available in all green, all pink, all purple, and a couple of other colors. My best guess is that the solid color ones actually are acetate, and that the whole bunch of rolls came from the same manufacturer in the same shipment along with my silk one, and whoever at Denver put them into the database didn’t take note of the oddball, other than that it was 5″ narrower.

So that’s how I’m going to explain this mystery to myself until any contradictory evidence presents itself. For those of you who were hoping I might write a nasty email biting the heads off of the folks at Fabric Mart, aren’t you happy just knowing that Denver Fabrics might one day send you surprise silk?