An example is the old mine cut, which creates a squarish stone with rounded corners and a high crown (the top portion of the diamond), a style popular in the Georgian and Victorian eras.

"Imagine all the incredible things lost to us because people just chucked everything into a dumpster," said one commenter on the viral video.

The diamond features an old mine brilliant cut, a style that predates the round brilliant cut used in engagement rings today. With fewer, larger facets, this cut suggests the stone was fashioned ...