The word magnetites 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: 16
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (35 words)
enigmas, gametes, gamiest, gatemen, gestate, inmates, instate, itemset, magnets, matinee, matings, matting, meanest, meanies, meeting, menages, mintage, mittens, neatest, negates, seaming, seating, seeming, segment, setting, sigmate, smitten, stating, tasting, teaming, teasing, teatime, teeming, tentage, testing