By Alexei Oreskovic

SAN FRANCISCO (Reuters) - Google Inc is expected to unveil its highly anticipated Nexus One smartphone on Tuesday, marking a first foray into an increasingly crowded market that could shape the future of the company's advertising business.

Gadget lovers around the world will focus on Google's corporate headquarters in Mountain View, California, where the Internet search leader is expected to announce the phone. But the tech world's fascination has not carried over to Wall Street, which is taking a wait-and-see view on Google's first effort to sell a hardware product directly to consumers.

Google's stock has risen about 7 percent since the start of December, setting a 52-week high of $629.51 on Monday. But analysts say that was driven by improvements in its core business of Internet search advertising, rather than the prospect of tapping a new pool of revenue selling smartphones.

Unlike Apple Inc's iPhone, which upended the mobile phone industry when it was released in 2007 and has helped propel Apple's stock more than 70 percent since, Google's Nexus One phone appears to be less of a game-changer -- at least from what is known about it so far.

"There's really not much that's groundbreaking at this stage," said UBS analyst Brian Pitz.

Many of the details of the Nexus One -- which Google has yet to confirm actually exists -- have trickled out via various Internet blogs, media reports and analysts in recent weeks, including technical specifications and pricing.

Early reviews in Barron's and the Engadget.com blog depict a device not drastically different than existing smartphones that feature Google's Android software, such as the Motorola Inc Droid and the HTC Hero. The phone has a large touchscreen, 4 gigabytes of flash memory and a 5 megapixel digital camera, as well as the latest, 2.1 version of the Android operating system, according to the reviews.

"Most investors would be neutral on this event near-term," said Kaufman Bros analyst Aaron Kessler.

"Longer-term, people are looking for stuff outside of search to drive revenue growth, but I don't think there's an expectation over the next year or two that that really happens from mobile in general."

SHROUDED IN MYSTERY

Technology blog Gizmodo.com last week said the Nexus One will be available for $180 with a two-year contract from Deutsche Telekom's T-Mobile USA, or for $530 for consumers who prefer to buy the device without a carrier contract.

Those prices are comparable to other smartphones on the market and unlikely to be "disruptive" to the industry's existing price plans, Goldman Sachs analyst James Mitchell wrote in a note to investors last week.