Board Thread:Ask the Staff/@comment-26609400-20150709045521/@comment-508329-20150716111114

In Warp Tour, they didn't seem to know that Peridot was a Peridot until she mentioned her name in her log entry, and the Crystal Gems don't seem to know Malachite's name (not until Steven learns it at the end of Chille Tid).

I'm guessing that Gems instinctively know their own names, and that the standard Gem types are common knowledge back on the Homeworld, but Peridot's a new Gem type that the Crystal Gems haven't heard of, and that Homeworld Gems wouldn't know the names of any of the Crystal Gem fusions unless they had a reason to know their names (for example, Jasper might know about Sardonyx from the war, and Peridot might've gotten some old wartime intelligence dossiers during her mission briefing).