Fine Sand

About 10s 0c on Beta · Horde (4 hours ago), 10s 0c on Beta · Horde (21 hours ago), and 1s 80c on Beta · Alliance (22 hours ago), from player scans. A vendor pays 1s 1c, so the auction house pays 9.4× more.

No. It is in Classic Era too, with the same item level, vendor price and stack size.

Sell it on the auction house. After the 5% cut a stack of 5 brings about 47s 50c there, against 5s 5c at a vendor.