Gem Propane Stove

Q: Recently I came across this antique stove, but I can't figure out how it works. The word "GEM" is in the middle of the base, but there are no other markings, serial numbers, or a city where it was made – nothing. I've gone to a half-dozen antiques stores and searched the web but I can't find a good match. The stove is 18 inches high and has three feet. The top is 10 inches across with a 5-inch opening where the grates are. There is a brass valve sticking out on the bottom that indicates it takes propane. I don’t know how old it is and I'd love to know its value. But even more, I would like to learn about its history. What company made it and when? Was it mainly upper-class people who owned them or did everyone have one in their house? Is it safe to use?