GREENFIELD — Coin experts across the region are sounding the alarm about an influx of fakes manufactured in China and infiltrating the U.S. market.

Chinese-made counterfeits of collector and circulating coins are more rampant than ever, according to the American Numismatic Association, having greatly improved in their deceptive quality since the 1970s. Still, many are relatively easy for a trained eye to detect and having a piece evaluated by an knowledgeable businessperson or graded by a professional company is the best way to avoid getting shortchanged.

“Well, I think [buyers] need to go to a reputable dealer,” said Gary Konvelski, owner of Gary’s Coins and Antiques in Turners Falls. “I just can’t believe the government lets [scam artists] get away with this stuff. They should be right on it.”

He said he has been in the business since 1993 and has owned his shop at 56 Avenue A for 15 years.

Konvelski said there is an undeniable recent uptick is the number of fake bullion coins, or coins made from precious metal and kept for their value or as an investment instead of everyday spending. This increase, he said, is due to record-high silver and gold prices. Konvelski said older people seem particularly vulnerable to being scammed on fake bullion coins.

“It’s just going to happen more and more,” he said.

The business owner said an older man recently visited his shop and sold a complete set of American Silver Eagle bullion coins ranging from 1986 to this year only to have to come back and return the money because, unbeknownst to him, the coins were fake. Konvelski said the coins were in holders issued by the Numismatic Guaranty Company — a respected coin-grading and certification service — but they did not weigh the ounce they were marked as weighing.

“It’s supposed to weigh 26.73 grams,” he said, walking a Morgan, or silver dollar to a coin scale, which revealed the true weight to be 21.9 grams. “They’re selling these on eBay, too, from China. You know, the normal person is not going to be able to tell the difference.”

Konvelski said he offers free appraisals. He mentioned he also has seen a lot of counterfeit 10-cent coins, particularly the 1916-D mercury dime. This piece is highly coveted because so few were minted. According to the Professional Coin Grading Service, another highly regarded coin-grading company, this is one of the most counterfeited of all U.S. rare coins and PCGS sees an average of five to 10 fakes per week.

But, Konvelski warned, online scammers even fake the slabs (the holders used to encapsulate coins) and the labels on them.

“It’s so hard [to tell],” he said.

He has in his possession, but will not sell, a fake PCGS-encapsulated Republic of China $1 coin with military and political leader Li Yuan-hung’s likeness. If it was real, Konvelski said, it would be worth $8,000.

Charles Hertan, of Charles Hertan Numismatics in Northampton, said he sees fake bullion coins in his line of work but the bigger problem is with rare U.S. coins.

“The Chinese are actually making three different tiers of fakes,” he said. “One tier is a basic fake, like a souvenir, and the top tier is designed to be deceptive enough to fool even a coin dealer. The takeaway from that is, don’t buy any expensive coins online unless you’re an expert.”

He said collectors, especially novices, should buy only from reputable dealers or from sellers with high ratings from eBay, Google or the Better Business Bureau.

“That’s going to tell you a lot, because reputation is everything in this business,” he said, “and we’re not going to risk our reputation.”

Hertan, who started collecting coins as a child and became a professional in 1990, said any reputable dealer offers a lifetime guarantee of authenticity.

He mentioned individual Chinese scammers have always counterfeited American coins, but they have stepped up their game in the past 15 to 20 years. A common fake, he said, is the Morgan dollar, even though it is not particularly rare. Hertan and Konvelski also advise people to steer clear of coins being peddled by telemarketers and TV commercials.

“The whole key is to deal with the right person, and value that relationship,” Hertan said. “The average person knows nothing about coins — the same way the average person knows about about plumbing or how to fix their car.”

Athol resident J.R. Greene said he recently turned down a fake 1955 double-die penny he was offered. A double-die coin is an error coin in which the design was accidentally struck twice or the die used was misaligned or damaged. This results in parts of the surface appearing almost blurry. Greene said the coin is rare because only about 20,000 were made before the error was noticed. If that 1955 double-die cent had been legitimate, Greene said, it would have sold for $1,500 to $2,000, depending on its condition.

He said people can train themselves to spot a fake but it is best to leave it to the professionals. He recommends the NGC, the PCGS, ANACS, and Independent Coin Graders. Greene mentioned counterfeit or ungradeable coins will be returned to their owner in a plastic bag known in the industry as a “body bag.”

He said casting methods used on Chinese-made fakes can cause bubbling on a coin’s surface.

“Real U.S. coins don’t have bubbles on the surface,” Greene said.

The longtime dealer also warned against buying coins via back-alley deals. He said if you’re buying a super-inexpensive coin, it’s for a reason and you’re getting your money’s worth, but not in a good way.

Greene started collecting coins as a 6-year-old and paid his way through college by selling coins at flea markets. He owned a shop in Athol in the 1980s and is now a vendor at coin shows and flea markets, selling coins as well as photographs, postcards, booklets and pamphlets.

He mentioned he keeps his personal collection in a bank safety deposit box and the coins he sells are kept in a storage unit.

An American Numismatic Association tutorial on Chinese-made counterfeits can be viewed at: tinyurl.com/ChineseCounterfeits. A list of reputable dealers can be found via tinyurl.com/ANAdealers.

Reach Domenic Poli at: dpoli@recorder.com or 413-930-4120.