Two former Wall Streeters found an elegant solution to the biggest problem with building a watch collection

The biggest problem with starting a killer watch collection - with some vintage pieces, of course - is making sure everything you buy is 100% authentic.

TrueFacet is the solution to that problem. It's an online retailer that buys and sells jewelry. More importantly, though, it appraises that jewelry and makes sure that every part of it (even the machinery inside a watch) is completely legit.

The company was founded in 2014 by Tirath Kamdar and Chris Chan, two childhood friends from Chicago. Chan is a former derivatives trader, and spent time at Capstone and Bank of America Merrill Lynch.

Kamdar cut his teeth working a JP Morgan, and at his family business Gemeralds, one of the largest jewelry retailers in the world. He also led marketing at Fab.com.

"When I spent 8 years in the jewelry industry, I noticed firsthand that when people were shopping or selling jewelry, they can go to 10 different shops and will get 10 different prices for the same item," Kamdar told Business Insider.

"Shoppers still did not know if the item they were looking at either online or offline, was actually authentic. It was very tough for anyone to purchase an expensive item not 'trusting' the source. Over 35% of items were counterfeit, 84% of people did not know what their luxury items are worth. It's a very opaque market."

Here's how the whole thing works:

TrueFacet buys and sells jewelry from luxury brands - from Cartier to Bulgari, from Tiffany & Co to Rolex. Prices range from $100 and $100,000 (including a Patek Philippe watch that sold for over $90,000). Appraisers on staff inspect every single one of the 30,000 items that goes through TrueFacet down to the last detail.

Usually shopper save about 40% on the cost of their purchase. For example, you can get a Cartier love bracelet for $4,200 as opposed to $6,750 retail.

Now, if you want TrueFacet to hunt something down for you, they've got a concierge service as well. All you have to do is text them and tell them what you're looking for, even if you just have a general idea what it is.

"People, especially guys, really need help when trying to buy gifts and are lost in this industry," said Kamdar. "Our concierge team has spent countless hours talking to guys during gifting season, guiding them through sizing and what to buy."

TrueFacet's supply has grown by 15%-20% a month since it was founded, but what its founders are really proud of, is their ability to track down rare items that their customers request.

"Recently, we had a request for the new Patek Philippe Calatrava Pilot watch, that is very hard to get and has barely hit the market," said Kamdar. "Many customers are on a waiting list for this at different stores. Leveraging our global contacts, we have this coming in next month."

Over the last month, Kamdar and Chan say their sales have grown 40%. They also have a new seller service planned for next year and plans to expand to key markets in Asia, EU, and Middle East in a year or two.

So start thinking about what you want and go ahead and ask.