While the creation process for most gemstones requires harsh environments and not a lot of it is created, it’s exponentially less likely still that two gemstones would grow into one another. However, on this vast planet we have enough crust to experience some strange phenomena. One of those is the creation of pseudomorphs, or mineral compounds where one stone grows into another.
While some of them look funky (particularly Goethite), the two gemstones don’t exactly combine to create something entirely new. Rather, one gemstone grows into the other and replaces any space it occupies. What it does make for, however, is some very interesting shapes. Here are some examples of Geothite growing together with Pyrite.
While that one is definitely the most alien-looking, you can get some pretty funky combinations when stones start to grow into one another. They’ll begin creating spots, weird lines, odd symbols and crystalline structures within one another.
So How Rare Is This Occurrence?
While it’s common enough to have an abundant amount to study and observe, it’s not common enough to hit the open market. Even still, a pseudomorph would have to be in a very precise condition to be aesthetically pleasing and, if it was, it would likely go on display somewhere. An art museum or a billionaire’s mansion, likely.
As unlikely as it is, the most common pseudomorph seems to be Quartz, as it’s one of the most common gemstones and one of the largest classifications.
Another major issue (as if we needed an additional one) preventing these from being publicly available is the fact that pseudomorphs are not very stable. When a rock grows into another rock, it just kind of takes over and forces itself in. This creates a ton of fault lines and, in a lot of cases, the pseudomorph will shatter with relative ease.