A former employee of Shreve, Crump & Low is accused of stealing tens of thousands of dollars in diamonds—in at least one instance replacing diamonds with cubic zirconia—from the venerable Boston Jeweler, The Boston Globe reports.

Tanya A. Nichols appeared in Boston Municipal Court Thursday, where she faced charges of larceny over $250, the newspaper reports. Released on personal recognizance, the 45-year-old Nahant woman did not enter a formal plea and was scheduled to be arraigned Feb. 9.

As she left the courthouse, Nichols denied to reporters that she replaced the jewels in two sets of diamond studs that were shipped from Shreve’s Boylston Street store to its shop in the Mall at Chestnut Hill last September.

In a Boston police report filed with the court, police reportedly said the “investigation showed that Nichols stole a large amount of jewelry from the store, and when staff discovered that jewelry had been stolen and conducted an investigation, Nichols began returning some of the items to the store.”

Police said in the report that $151,000 in jewelry is still missing, the newspaper reports.

The store’s security director told the newspaper that Nichols was videotaped suddenly discovering jewelry that an audit showed had disappeared from the store. Nichols was hired last March and fired Oct. 6 as a result of the larceny investigation, he reportedly said.

One set of allegedly stolen studs was worth $87,000, and the price for the second was about $50,000, the newspaper reports. He said the swap was discovered before the items were put on display in Newton.

Nichols learned that employees were going to be forced to take a polygraph test as part of the investigation and she got scared and began returning the stolen items, the detective told the newspaper.

In one instance, Nichols is accused of returning an item to a “hold box,” a storage area for jewelry set aside until the buyer finally makes a purchase, the detective told the newspaper. He said she is then seen on security cameras making a cell phone call to the store, where she pretends to be a customer who wants to know whether a particular piece of jewelry is in the hold box. Other staffers then found the missing jewelry in the box, he said.

Shreve’s traces its corporate history to a store in 1796 in Boston, across the street from Paul Revere’s silversmith shop. Current owner David Walker took the company out of bankruptcy proceedings in 2006.

JCK