Here is another estate sale purchase. Tabriz? Dimensions:9'9” x 14' 3” I have accouple concerns about construction material. I first walk away from this because it seem way to soft for wool on cotton and was thinking it was mercerize cotton. The seller allowed me to pull a few knots and I did a field burn test. It clearly burned like a protein fiber and not a cellulose fiber. I've attached a picture. It smelled of burning hair not burning paper and it more melted than burned. If this is inconclusive I can do a copper sulfate test. Any thoughts on the rugs origin, age, value. I know the rug to be early 70s or older as I was in the house as a child in the 70s and remember the rug.

Thanks. I'm still better than break even. I'll throw it down in the family room and just use it. Is it worth verifying with a cooper sulfate test? Fortunately I'm a chemist and can access copper sulfate pretty easily.

I am curious of your conclusion it's synthetic from the burn test. Everything I have read indicates most synthetic fibers are cellulose based (ex Ryan)as well as mercerized cotton and don't melt but rather burn to a grey-white ash. I have tested Ryan before and it burns to an ash. I'm still at the bottom of the learning curve but tend to approach things analytically. Your insight is greatly appreciated.

Cheers

Andy

I'll get the cooper sulfate and see if I can dissolve it. Hell, if I want to really geek out I can run an IR spectrometer. That would be chemically definitive. I'll let you know the results.

Cheers

Andy

OK...here are the results of the cool science project. I re-accomplished the burn test. It self extinguished, smelled of burning hair and left a tight black ash. (see attached) From all the literature this indicated a protein based fiber wool or silk. I confirmed this with the Copper Sulfate "Biuret" test for proteins. The Biuret reagent turns from blue green to violet or dark purple in the presents of protein. Cotton and all common synthetics don't contain protein. Cotton is cellulose. In the attached from left to right is a known cotton fringe sample in the reagent. No reaction. next is the reagent alone, third is the reagent with human hair. Dark purple. On the left is the sample from this rug. It turned violate. Proof the knots are protein based. Again from the literature, the next test is microscopic analysis. Attached are picture at 1000 x magnification of a known wool sample and this carpets fibers. Wool will be a thicker fiber than silk with a course scaly finish. Silk has a much smaller fiber that is smooth with small nodules that can appear translucent

The first time that I have seen scientific approach on this forum and is always very welcome, as you can't argue with science. Well done.