The word chalkstones is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 22
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (46 words)
alecost, anklets, ascents, cantles, caskets, castles, chalets, chaoses, chasten, cholate, clashes, closest, closets, clothes, enlocks, ethanol, hackles, hastens, hatless, hostels, hotcake, hotness, lactone, lactose, lancets, latches, leantos, loathes, locates, lockets, lockset, notches, octanes, sachets, satchel, scathes, secants, shackle, shlocks, slacken, slocken, sockets, solaces, stances, stanols, tackles