What grade sandpaper might this be?

i found some sandpaper from earlier this summer when i 'attempted' to lap a heatsink. i just don't remember what grade it is. sorry that i don't have a pic. i will give you the best description possible. the colour of the paper is a dark rusty brown, (according to my wife). on the back of it there are certain words and guess number codes. they are:

CROCUS
N-72
FINE

does anyone know what grade this might be? thanks for any help that you may be able to provide.

it might be 500 or something. but probably not fine enough for lapping. you need 1000 or 2000 grade for lapping.

yeah, i have 1500 grit but i was just wondering what the heck i had here. when this stuff gets wet it gets kind of creamy. just don't know the grade. thanks though.