TUCSON – The 66^th Annual Gem and Mineral Showcase is in full swing.

It’s expected at least 60,000 people from all over the world will be in Tucson to buy, sell, or trade gems, jewelry, and miscellaneous items.

When it comes to gems, how you do know if you are getting the real deal?

Noor Mohamed proudly showed pictures of the world’s largest Cambolite natural stones.  Total carat weight was 84. He sold them last year at the show here in Tucson.

Mohamed comes from Malaysia and he is also a graduate gemologist. 

Cambolite is also known as a Blue Zircon.

Mohamed said Cambolite is not a very expensive gem nor is it cheap. He said it’s priced in the middle and makes it very attractive to designers. Yet, there are some who will try to sell it as the real deal when it might be a colored piece of glass.

“You need to know the people you are buying from and have a good reputation so you can be confident that he is selling the right stuff,” Mohamed said. However, he added, “People who are new to the market they will try to mix together one or two fake stones and then they will make their money and they go away.”

That's when Monica Caldwell sees people who've been cheated. Caldwell Jewelers has been in business 40 years here in Tucson.  She’s a graduate gemologist who specializes in diamonds.

Caldwell takes out a tray and talks about the four stones on it:

“This is a lab grown diamond, this is a natural diamond, this is moissanite, and cubic zirconia,” said Caldwell.

Each were 1 ½ carat.  The most expensive the natural diamond worth $9,000.  The least expensive, the cubic zirconia valued at $5.

Caldwell said at the gem show, under fluorescent lights, it’s pretty difficult to tell what’s what.

That’s why she suggested you buy from a reputable dealer, and go to a graduate gemologist to look examine the stone.

“They won't necessarily give you an appraisal they will be able to identify it for you,” Caldwell told News 4 Tucson.

She also suggested getting information about the item you purchased in writing.

“I would get a written receipt and make sure they put the item, if its Tanzanite, if it's a topaz make sure they write that on the receipt," said Caldwell. "Make sure they write the carat weight on the receipt that gives you recourse just in case you find out it's not what they represented.”

Another tip: whenever possible, buy local or from a reputable vendor.