If there’s a black diamond logo on the spine of the case, your old Disney VHS tape could be more valuable than you think.

Ever since its 2007 release, rumors have persisted that The Poughkeepsie Tapes are 100% real, and that director John Erick Dowdle somehow got a genuine snuff movie put into circulation.

Centimetre-sized flexible diamond films have been produced by researchers in China, who grew them and then exfoliated them from a silicon substrate using Scotch tape. The researchers believe the films ...