Apple's  quarterly profit almost doubled, blowing past Wall Street estimates after a jump in iPhone sales, particularly in the greater China region, and soothing fears that the iPhone was past its best days for sharp growth.

Shares in Apple, the world's most valuable technology company, shot 7 percent higher after the bell, recouping some losses from the past two weeks that had stemmed from concerns that iPhone sales growth rates could not be maintained.

While iPad sales were a little lighter than expected, fiscal second-quarter revenue jumped to $39.2 billion, 59 percent more than a year earlier and 6.5 percent higher than analysts' average forecasts.

Lower-than-expected commodity costs also helped lift margins way above estimates. "That shows they are able to maintain their pricing without compromising on growth," said Morningstar analyst Michael Holt.

Holt added that this had come even though lower priced competition from Google Inc's Android phones - made by the likes of Motorola Mobility and Samsung Electronics  were becoming more compelling.     

"The concern was that Apple might sell more older models to be more competitive. That would have shown up in the gross margin. But aggregate gross margin and average revenue per device show that this hasn't happened," he said. 

Apple sold 35.1 million iPhones - which account for about half its revenue - in the quarter, outpacing the 30 million or so expected by Wall Street analysts, with pent-up demand for the 4S bolstering revenue for China, Taiwan and Hong Kong five-fold to $7.9 billion.

"International iPhone sales were on fire," Apple Chief Financial Officer Peter Oppenheimer told Reuters in an interview. But sales of the iPad, the latest version of which hit store shelves in mid-March, came in at 11.8 million iPads, below an average forecast of up to 13 million. - Reuters