I love all phenomenal stones, esp color change and cat’s eyes. It’s equally fascinating and fabulous that once in a while a color change Alexandrite is also a cat’s eye 
I’ve seen photos of amazing color change Tourmalines, but I’ve seen lots more pics of cat’s eye ones.
I used to give jewelry store employees a treat whenever I’d hand over a Moldavite ring for a free cleaning. “Please show this to your gemologist after it’s clean - they’ll have a lot of fun with it.” Sometimes the person who waited on me would start wondering what it was - nothing else is Moldavite green. Sometimes all the employees would come along, grinning, to give back the ring and ask what ahem on Earth it was! They’d recite a list of gemstones it was sort of like but obviously not, then tell me, “It looks like glass when it’s magnified, but…” and I’d tell them it is glass, but it’s an impactite or tektite. I’d explain that the glass was formed when meteorites struck the Moldau valley and environs, and that bubbling is obvious in many rough pieces. Back in the 90s no one knew what it was, and they were always really happy to learn about such a weird stone. I’d thank them for cleaning it, but they wound up thanking me more for hipping them to a new gem.
Not long after learning about Libyan Desert Glass (another impactite), I was re-reading a book about Tutankhamon. I came to a great pic of this:
and immediately realized the center scarab
is Libyan Desert Glass. It had been misidentified as Chrysoprase, and those familiar with it will understand why. The scarab does indeed have a very Chrysoprase-esque inner glow.
Well over a decade later, a vacationing scientist who was visiting the Cairo Museum saw the pectoral, and reached the same conclusion. He spoke with the museum’s honchos, and it was discussed with more honchos, who eventually agreed to running tests. The tests determined that it is indeed LDG. LDG is 98% silicon dioxide, making it the purest glass in existence.
I attended the late 70s Tut exhibit in Chicago as a kid, and that pectoral was one of the many breathtaking displays. I’ve never forgotten “meeting” the strange, glowing golden scarab.
It has been much more recently determined that LDG was formed by a meteorite’s impact, not by an airburst, after traces of Reidite were found in the microscopic Zircon crystals in the area’s rocks.
The Detroit Zoo has some glowy critters in the Reptile House. A UV/black light comes on every few minutes so the critters (what aren’t hiding) show off their glowiness.