Have you heard of Moissanite? It's a very rare mineral discovered by 19th-century chemist Henri Moissan in Arizona's Meteor Crater. At first, he thought it was diamond, but later realized it was even more rare. It's a diamond lookalike that, until the 1950s, was found naturally only in meteorites.
 
On Aug. 2nd, 2025, the students of Earth to Sky Calculus launched this Moissanite pendant to the stratosphere onboard a cosmic ray research balloon. At the apex of the flight, it floated 109,620 feet above the Sierra Nevada mountains in central California.
 
Engraved with the words "I love you always and forever," the sterling silver frame curves around the Moissanite in the shape of a heart--all highlighted by glittering 5A cubic zirconia nuggets. 
 
During the 3-hour flight, the pendant experienced temperatures as low as -58 C and air pressures less than 0.09% of sea level. Cosmic ray levels were 100 times Earth-normal as the pendant reached the top of our planet’s atmosphere and touched the edge of space. 
 
The students are selling space pendants to pay the helium bill for their cosmic ray ballooning program. Each one comes with a greeting card showing the jewelry in flight and telling the story of its trip to the stratosphere and back again.