Luxe Silicon Valley real estate at bubble levels?

If you think Apple or Facebook stock is expensive, look at the price of real estate near their headquarters.

Call it the housing bubble 2.0.

While real estate in much of the country is hitting a slow patch, luxury home sales in Silicon Valley are soaring nearly as fast as Facebook (FB) stock.

Sales of homes in San Jose, California, priced at $1 million or more jumped 76 percent in 12 months ended in July, according to the "Luxury Market Report" from Coldwell Banker Previews International. Sales of homes priced at $10 million or more have doubled in the posh Valley neighborhood of Atherton.

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"The strength of the tech sector is generating a lot of wealth that's being invested in real estate," said Joyce Rey, a Beverly Hills Realtor and luxury real estate expert with Coldwell Banker. "I think it will continue this year."

San Francisco ranked first in the country for sales of $1 million-plus homes, with a total of 2,485 sales in the period, according to the report. That was followed by Los Angeles, with 2,170, and New York with 2,145.

The number one ZIP code for sales of above $1 million was Burlingame, California, also a popular spot for Silicon Valley techies. Burlingame's 94010 ZIP code easily outpaced the famed 90210 ZIP code in Beverly Hills, California, with 404 sales compared with 295 in the Hills. (Yet Beverly Hills was still the top ZIP code for sales of homes priced at $5 million-or-more and $10 million-or-more brackets).

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The question, of course, is how long Silicon Valley real estate will continue its euphoria. The Internet is filled with pictures of old cottages or weed-covered shacks in Silicon Valley listed for a half million or more.

Since most buyers are paying cash, the current housing boom in the Valley is less risky than the boom in the mid-2000s, which was fueled by overly generous mortgages, Rey said.

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"The previous cycle we had people getting credit who had no ability to repay," she said. "The vast majority of these deals today are cash."

Of course, all that cash—and the fortunes of its owners—is coming from highly volatile tech stocks. If they fall, demand for Silicon Valley would fall with it.