Need help with yarn requirement

I’m contemplating crocheting an afghan for my mother, but need some help figuring out the yarn requirements. We saw a photo of an afghan worked in Noro Kureyon Sock in one of the current crochet mags at B&N. It’s one huge granny square, and it was fabulous. As it’s in an advertisement, of course there is no pattern easily available and I haven’t had any luck with google.

For a 60" square afghan, crocheted in one very simple granny square, how much yarn do you think I might need? I found the pattern for the Babette Blanket from IW Crochet which is 40x43" and it called for 3500 yards of Koigu, which is also a fingering weight. However it’s 19 skeins of mostly different colors and who knows how much of that is leftover at the end, whereas with the Kureyon, I’d only use one color for it’s striping ability.

Any thoughts? I’ve found a site that has the Kureyon Sock discounted nicely, and I’d love to order it before it is no longer on sale! TIA!

And with the Babette, some of the yarn is used to connect all those squares. Here’s one that’s made in one rectangle - - and though the original doesn’t say how much was used, some of the projects on ravelry with only one or 2 colors were made from about 1000-1500 yards with an I or J hook. No sizes were given other than `throw’ size.

sue, thanks, but can you tell me how 1000-1500 yards with an I or J translates to sock yarn with an E hook.

let’s try another tactic - does anyone have the magazine that we saw, it was either IW crochet or another mainstream crochet mag, and can you tell me what yarn store the ad was for? the ad was on the bottom half of a right hand page, and it says “noro kureyon sock”. if i can find that out, i can contact them directly and hope that a friendly person who can help answers the phone.

Ooops sorry, forgot about the yarn weight…

I actually have a pattern I bought for a Crochet Granny Sqaure Throw made with Boku yarn. It calls for 2 balls of 6 colors of 50g balls. The square is worked with 1 strand of each color 1 and 2, then 2 and 3, etc. with a size M hook. The size is a 42" square.