It is a nice silk. Not the very thick silk as the Heart-throb boyshirt. Some people say they don't like about its sheerness. But I find it acceptable as it is black and not a light base color.
However, I find the fit a little strange. I am usually between a size 4 or 6 for J. Crew shirts. I took a bigger size of 6 for this one. It fits nice but I find it a little wee tight around the armpits, i.e. it would be hard to lift your arms up high when I'm wearing this shirt. Also, the back is a little longer than the front which I don't have a problem with. I think it would be great to pair with skinny jeans to hid the behind :)
Banana Republic Cardigan (sim here)
Tiffany Open Heart Pendant necklace
I got this before the non-stop J. Crew promo in the past 2 weeks. So if you are obsessed with polka dots, don't let this shirt get away. There is a 30% off final sale items (use promo code: MUSTHAVE) and this top is not on final sale. I know a lot of people won't buy items on final sale, thinking it is a gamble on items which they haven't tried on before.