I got curious about the weight of the fabric I was weaving, so I weighed one pirn of the 140/2 silk, then measured the length of cloth I wove from that one pirn. Believe it or not, I wove for TWENTY-SIX INCHES on one 13-gram pirn! At that rate, 20 yards will only require about 13 ounces (well under a pound!) of weft. Egad.
I then did some more calculations. 96 ends per square inch of fabric = 2.66 yards per square inch of fabric, at 15,000 yards per pound. Skipping over some tedious calculations, that’s roughly 3.7 ounces per square yard in the warp. At 60 picks per inch, there are 60 inches of weft in every inch of fabric, and at 35,000 yards per pound that’s almost exactly ONE OUNCE of weft per square yard!!
Adding the two together, of course, makes 4.66 ounces per square yard. Since 21 yards of 24″ fabric is only about 14 square yards, this means my completed 21 yards of fabric will only weigh about 4 pounds.
Just for fun, I converted into momme, the standard weight measurement for silk. It comes out to 36 momme, which makes it a trifle lighter than double-faced, heavy bridal satin (which is 40 momme). So I think it might be OK for wearing, though I still don’t know about putting a coat over it.
All of which boils down to, this is damn fine fabric. In all senses of the word.