NO ONE KNOWS why it is, something in the water maybe, but Texas has turned out more than its share of rock and blues guitarists, among the latest being Mason Ruffner.

"Gypsy Blood," Ruffner's second album, bears the unmistakable stamp of producer Dave Edmunds and also reflects Ruffner's years in New Orleans. To Edmunds' credit, the album packs a strong rhythmic punch, strong enough to redeem even derivative songs like "Dancing on Top of the World," and to compensate for those moments when Ruffner's agonized voice verges on a parody of Jimi Hendrix, Bob Dylan and Graham Parker.

The best songs include "Baby, I Don't Care No More," in which both Ruffner and Edmunds sustain a loose New Orleans groove reminiscent of a Clarence (Frogman) Henry recording, and "Distant Thunder," a song of love and redemption capped by a flowing guitar solo. Moreover, a galloping instrumental called "Courage" provides further evidence of Ruffner's sterling guitarmanship and his obvious gift for fashioning sharp melodic hooks.

"Get Lucky" by Lucky Seven is more of a dance album, a genial, if somewhat uneven, collection of tunes which often combine elements of rock, Cajun and zydeco music. The quintet's songs tend to be slight, merely excuses for dancing, but then there's nothing wrong with that as long as accordianist Kenny Margolis is breathing life into tunes like "Rosalie," "Cajun Man" and the delightfully reckless "Don't Know Why." Although the rest of the album isn't nearly as consistent or enjoyable, the band does have some interesting things to offer, including a stately Celtic arrangement of Dylan's "Only a Hobo." MASON RUFFNER --

"Gypsy Blood" (CBS BFZ 40601).

LUCKY SEVEN --

"Get Lucky" (i.e. 7LP).

Both appearing Saturday at the 9:30 Club.