F-35 Fighter Jet Window Sapphire Loose Calibrated Gems (F35 Gem)

These are lab created sapphires which were grown for use as a sensor window in the F35 fighter jet but didn't meet spec.  They've been faceted and are available as loose gems! Note that the calibrated cuts have a bit more size variation than usual, up to a quarter mm. These stones glow blue under shortwave UV because of titanium contamination.This is a really cool material--lab sapphire grown for windows on the F35!  These aren't used on the cockpit but on a sensor array right below.  There are numerous sensors on the bottom of an F35 that allow for a 365 degree view in a wide spectral range.  With the incredible accelerations and speed that have to be withstood an ultra hard, ultra durable material like sapphire is needed.  But how do you make giant, flat sheets of sapphire?  Normally you'd cut windows out of a big round boule grown by HEM or kyropolis but the shape really isn't conducive to larger flat shapes. To solve this problem Rubicon, at the time one of America's greatest sapph