Beautiful clear crystals that sparkle like diamonds. When spun around, they reflect a different refraction of reality. But their larger secret lies in what occurs when they are charged with Elemental magic. Once they are, they are no longer a small party trick and will literally cut through the fabric of reality to another. As such, they are incredibly valuable for their ability to create portals to other universes where Gold can be harvested. Smaller charged shards of the crystals are also used in Crystaltech, and allow for most of the computer technology around Erina. They also allow the transport of any large amount of goods, resources, or soldiers, as they can also be used to create portals within Erina. This makes them vital to almost everyone and every industry in Erina, and many cities have their roots in being mining settlements created exclusively to extract the crystals.
A shimmering crystal that bends all the light that shines through it.
Geology & Geography
Enigma crystals are only found underground, though there is no real rhyme or reason of where underground. Deposits just pop up randomly, and it is greatly attributed to the Gold's influence on the land. More often than not, it is found around other precious materials, and only found because those are already being mined.
History & Usage
The humans that existed in Erina often found it to be an amusing material. It wasn't that common, it wasn't diamond, but being able to see different versions of reality through it was kinda neat. While no records exist, it's likely that some people saw more in the crystals than just being a party trick, and they may have found spiritual meaning in them. But that is just speculation. For the Elementals, it's one of the most valuable materials that exists, and so far has only been found on their world. Its importance is reflected in the name of their currency, Jewels, which directly relates to the crystals being used in exchange for goods. Want a sandwich, give the military a crystal. They aren't used for bartering in the modern times. Though, bringing knowledge of a new crystal mine to any organization will lead to you being compensated extremely well.
Engima Crystals appear a lot like diamonds, except they always contain the same amount of refraction regradless of their cut