Hawaii has 10 main islands — not eight — in 10 commemorative Hawaii quarters that Wai­alae Iki coin collector Joe Au-Franz has found so far.

And while digging around in his pockets and change for more of what Au-Franz calls the "extra islands" quarters, Au-Franz last month began coming across 75 more faulty commemorative quarters that show extra markings near Hawaii island.

Because of their seemingly low numbers, the "extra islands" quarters that made their way out of the U.S. Mint in Philadelphia are "like the Holy Grail" for people who collect error-filled coins, Au-Franz said Sunday.

Au-Franz, 52, started out collecting buffalo nickels, wheat pennies and Mercury dimes as a kid on his paper route in Erie, Pa. More recently he wrote an article on his latest discovery of the "extra islands" quarters for the current issue of ErrorScope, the magazine for CONECA, the Combined Organizations of Numismatic Error Collectors of America.

"You can see the extra islands with the naked eye," Au-Franz said.

He hopes his discoveries spur people in Hawaii to look for more of the incorrect Hawaii quarters and will speak about them at 7:30 p.m. Wednesday when the Hono­lulu Coin Club meets at the Susannah Wesley Community Center on Kaili Street in Kalihi.

The presentation is free, the public is invited and Au-Franz will auction off — or donate — one of his quarters with the extra island features — a lava shelf, Loihi seamount? — to benefit the Hono­lulu Coin Club.

"I’m not selling any of the ‘extra islands’ quarters," Au-Franz said. "Those are rare."

Au-Franz, the father of three girls, especially hopes the error-filled quarters help renew interest among Hawaii children in coin collecting, an interest spurred when the U.S. Mint released its commemorative Hawaii quarters on Nov. 10, 2008.

"It’s a real fun hobby," Au-Franz said. "It’s something you can do in your free time just looking through your pocket change."

Officials at the U.S. Mint were unavailable for comment Sunday.

Mike Ellis, vice president of the 700-member CONECA and a member of the board of governors of the American Numismatic Association, said errors known as "a die variety" have been found in other state’s commemorative quarters, especially quarters produced in the Philadelphia mint.

"With these state quarters, there was seemingly a higher number than usual of your typically encountered die varieties," Ellis said. "In my opinion, quality control at Denver is better than at Philadelphia."

Commemorative quarters featuring Minnesota and Oregon, for example, had parts of extra trees that made their way into general circulation, Ellis said.

But Au-Franz’s "extra islands" quarters are special compared with the problems with the Minnesota and Oregon quarters, Ellis said.

"Those weren’t cool like this one," Ellis said. "‘Extra islands’ is a catchy name, and with coins that have a catchy name, for some reason people scarf them up."

Ellis theorizes there was a faulty die in Philadelphia that cast the "extra islands" quarters that "makes the whole map of the Hawaiian Islands look totally different."

And unlike the Minnesota and Oregon quarters, the mistake in Hawaii’s commemorative quarter is clearly visible and occurs in a clear area of the coin, Ellis said.

"It’s definitely not typical," he said. "All of those extra islands are out in such a clean field, so they stand out even though they’re small. Because it’s a whole lot easier to spot, this one will definitely attract some attention."

But how much are they worth?

"I have no idea," Ellis said.

Au-Franz theorizes that someone or something came into contact with the die used to make some of the 254 million 2008 "P" Hawaii Statehood quarters at the Philadelphia mint, and a gouge in the die created two additional islands south of Oahu and Molokai that are nearly as big as Kahoolawe.

He had received one of the first Hawaii quarters in 2008 and immediately put it in a little cardboard "flip" featuring a clear plastic window. Whenever Au-Franz found another nearly mint Hawaii quarter in his pocket change, he’d add those to his collection, as well.

Then in January 2009 he was surfing eBay and came across a Hawaii Statehood quarter featuring the two extra islands. He bought five of them — at $10 apiece — and compared them with the other near-mint quarters in his collection and realized that he already owned three "extra islands" quarters.

As he added two more "extra islands" quarters to his collection, Au-Franz began searching for even more.

Then last month a co-worker at the Pearl Harbor Naval Shipyard brought Au-Franz several rolls of quarters and found one that had funny marks between Kamehameha and Hawaii island.

"He handed it to me and said, ‘What is this?’" Au-Franz remembered. "We couldn’t believe what we were seeing."

By superimposing images of the front and back of Hawaii’s Statehood quarter, Au-Franz believes the three to seven extra marks he’s found are the result of George Washington’s hair coming through the back of the quarter.