Story highlights The "iPhone 5 Black Diamond" is estimated to be worth $15 million

Black diamond in the home button was appraised at $14.5 million

Lavish UK craftsman Stuart Hughes was contacted by Chinese businessman

Rare, black diamond has been in the family for generations

Family heirlooms are often packed away for safe keeping. For one man from China, hiding a 26-carat black diamond worth $14.5 million was not in his plans.

A businessman from Hong Kong commissioned craftsman Stuart Hughes of Liverpool to help him show off his family treasure.

The result? An iPhone 5 boasted by Hughes to be "the world's most expensive phone," valued at $15 million.

According to Hughes' website, this iPhone includes 600 flawless white diamonds, a full solid gold dressing and 53 diamonds on the rear that make up the iconic Apple logo.

However, the reason this particular iPhone is so valuable is on the face of the phone.

The Chinese businessman, identified only as "Joe," contacted Hughes and asked to have a rare, black diamond incorporated into the iPhone.

"It's not often that people get to deal with a very, very rare diamond," Hughes said.

Hughes said he was contacted 18 months ago by Joe, who expressed interest in his gold chassis iPhone handsets.

Joe then told Hughes about the black diamond that had been in his family for generations. Hughes spent nine weeks creating the solid gold chassis of an iPhone 5 and then placed the black diamond as the home button.

The appraisal Joe had done on the black diamond put its value at approximately $14.5 million, according to Hughes, who said he saw the certificate of authenticity.

Hughes told CNN that one of the solid gold handsets with the diamonds that he crafts is worth approximately $153,000.

"We had a tech guy in Macau who was able to set the stone, which to this day has never left China," Hughes said.

Hughes set a record in 2011 for crafting an iPhone 4S with 500 individual diamonds, totaling more than 100 carats. That phone was estimated to be valued at $9 million.

The 42-year-old craftsman is known for making lavish and expensive items, including an iPad made of solid gold he debuted two years ago.

"I am a craftsman," Hughes said. "I basically fulfill and make up these ideas."

Throughout the years and his many projects, Hughes said this particular handset is right up near the top of the most lavish projects he's completed.