These are very poor quality paper. In my opinion the only thing that qualifies them as index cards is their dimensions. I wasn't looking for anything fancy but I expected slightly heavier paper. To describe them as "sturdy" card stock is wildly inaccurate. I only purchased them because the similar product made by Oxford was out of stock. I won't make the same mistake twice.
I needed just 200 unlined (blank) 4X6 cards but the ONLY quantity available was 500 which I was therefor forced to buy as there was no other nearby source of the cards. The cards are no better than just okay (or "good" as in Good-Better-Best) as they are thinner than I would prefer. Again there were NO alternatives.
I bought these to make 75 Valentine's day cards for my three girls to give to their classmates. We folded them decorated them with ink stamps and punched holes to insert a lollipop in each. We also will use them to make gift tags invitations and Thank You notes. 500 seemed like a lot of cards but I think we will go through them quickly.