They're about five grams each I think, for a total of half an ounce of silk. I spun the one in the bottom right corner this afternoon:
It was so much fun to spin, and so soft. I spun a very fine yarn, probably lace weight, and got about 30 yards out of it. I can't wait to start the next one.
While 15 grams won't give me a lot of yardage, I can't complain; there was also 1 pound (!) of 100% silk and 1 pound of a wool/silk blend, so I'll have lots of joyful spinning to keep me busy in the next few months.