The word peridots 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: 12
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (22 words)
deports, deposit, diopter, dioptre, dopiest, editors, peridot, periods, posited, roisted, ropiest, sortied, spirted, sported, steroid, storied, striped, tierods, topside, torpids, tripeds, tripods