A loupe is a magnifying glass that you can buy at any jewelry store and will let you take a closer look at your gem and setting.
"When you're looking at a diamond, there are a few things you'll notice," Hirsch told us. "First, the majority of diamonds are made in nature so that means you're going to see some imperfections in the carbon. A fake stone would be perfect — absolutely perfect."
Hirsch explains that certain lab-grown stones will also look perfect through the loupe, and so you should be cautious before discarding perfect gems. It can be a clue, however, that you should take a closer look or bring the stone to an expert.
Second, observe the diamond's edges. "When you're taking a look at a diamond through a loupe, a real stone is going to have sharp edges, and a fake stone will have rounded edges," Hirsch explained.
Lastly, look at the mounting and etchings, especially any marks that signify what metal was used. "If the metal is gold-plated or silver, chances are it's not a diamond, because why would you put a nice stone mounted in such a cheap metal?" Hirsch said. "Most diamonds are mounted in gold or set in platinum."
"Also take a look at the mounting itself and how that diamond is set," she added. “If the setting looks like it’s of poor quality, that probably means it’s not going to be a real diamond either.”