The hottest pot store in San Francisco

It's referred to as the Apple store of pot shops.

Sparc is one of the premier medical marijuana dispensaries in San Francisco. Founded in 2009, Sparc now serves up to 400 customers a day who can pay $300 for an ounce of marijuana.

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Why is Sparc the go-to destination for weed lovers?

One, the shop boasts an award-winning design with warm lighting and communal tables. It feels more like a high-end wine bar than a pot shop.

Robert Jacob, its executive director, is also unique: In addition to running Sparc, he's the mayor of Sebastopol, California.

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"If you walk into any other business, whether it's a restaurant or food service business, they put a lot into the atmosphere and customer service," said Jacob. "Sparc wanted to do the same."

Customers, in order to buy marijuana at Sparc, need to be at least 18 years old, and carry a letter of recommendation from a physician. Sparc also partnered with a start up called Eaze, which delivers weed directly to customers' homes.

"Sparc really stands out as a leader in the space," said Keith McCarty, CEO of Eaze. "They exceeded our expectations around quality assurance and the professionalism of their member services."

The dispensary operates as a nonprofit so it keeps only the money necessary to run the business day to day. Surplus funds, Jacob says, are donated to charities in San Francisco.

Business at Sparc is booming thanks to the growing legal marijuana market. America's cannabis industry reached $1.5 billion in 2013, according to The ArcView Group. The sector is estimated to balloon to $10.2 billion by 2018.

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Jacob said that kind of growth makes the marijuana industry a smart place to invest.

"This is an excellent place for investors to put money in," he said. "When you talk about the new venture, the new place where capital is growing, the next hot thing, this is it."

Investors are excited about the potential opportunity of marijuana, but there is still uncertainty about how quickly legalization will come to California and the rest of the country.