Crystalline Cave

The crystalline caves are naturally occuring caves specific to the Other Side of the World, as they require a vast quantity of concentrated mana to form. The process could take up to hundreds of years, depending on the fluctuations of the manastream. That is because the crystallization of mana requires the particles of mana from a manaastream to latch onto specific mineral deposits. The most common basis for the formation of a crystalline cave is a calcareous cave, moreso if the cave contains many speleothems, especially columns, stalagmites and stalactites that can restrict the flow of the manastream through the cave system. Mana must condense on top of an existing mineral structure; the structure will act as a foundation for the growing mana crystals. Over many decades or centuries, the walls and speleothems of the cave will be covered in a shimmering layer of mana crystals, making the cavern glow dimly with a bluish-purple color.
Exploration of such caves is not advised; the high concentration of mana inside can induce dizziness, nausea, fatigue and weakness. If you begin to feel as such, leave the cave immediately and take preemptive actions against mana overexposure: use your innate abilites to eliminate the excess of mana from your body, keep distance from mana-rich areas and apply Karhneoloa sap on your exposed skin.
For those determined to explore these natural wonders, it is important to read all the information available about the ecosystem and geology of a crystalline cave. These cavern systems often house dangers, both in their depths and close to the surface. Always make sure you are properly equipped to explore such a cave; you should also seek the companionship of other explorers instead of venturing on your own, in order to increase your safety.

Wildlife

Flora: The flora of a typical crystalline cave is a little more diverse than what it is usually seen inside cave systems. Because of the unique nature of its geology, the ecosystem can support a larger variety of grasses and mosses. Most species inside such caves have evolved to replace solar light with the luminescence of mana crystals; patches of greenery are more commonly found deeper inside.

Funga: If the crystal stalactites and stalagmites appear covered in translucent goo, do not touch it with your exposed skin. The substance is the mycelium of a very dangerous type of fungi: the manaseeker fungus, a species that aggresively consumes the mana of the object it grows on. In order to penetrate the crystalline structure of its support, it is theorized to have evolved piercing roots that slowly absorb the concentrated mana inside. If you ever encounter this fungus in the wild, immediately leave the cave, avoid close contact with other people and ask for help from a Exalt who studied Alcehmy, Botany or Anatomy. The fungus is capable of growth no matter the environment and not even dwarven skin can protect against its roots. It will act as a parasyte and suck its host dry of blood and mana, before continuing to expand, devouring internal organs, flesh and eventually bone. Manaseeker fungus spores are very heavy; there is very little to no risk of airborne contamination. Always look around for darker spots inside crystalline caves and always wear protective equipment with low mana concentration (unenchanted steel plating is considered the best and most viable option).

Fauna: The fauna of these caverns resembles that of its "normal" counterparts, with the exception of evolutionary traits that allow these creatures to thrive in mana-dense regions. The geode mouse is one such animal; its subspecies is probably the most common, as the abundance of flora and lack of predators allows smaller rodents to thrive in this ecosystem. Its fur and skin both provide mana insulation; because of this, many mining teams include a dedicated hunter to catch mice during mining operations, as the animals do fetch a good price in specialized markets.
There is, however, one important exception to this rule. As most of the crystalline caves form in proximity to the Rift (and almost all of them in nearby areas inside the Other Side of the World), these places are oftentimes used by crystallis drakes as mating grounds and dens. The telltales of a crystallis drake den/mating ground are simple, assuming one has prior knowledge of other drake species: the tidy entrance, scratchings on the walls near the mouth of the cave (vertical for a den, crossing on the diagonals for a mating ground) and spaces larger than 20 darhii across. Under no circumstance should you approach such caves. During mating season, up to 20 drakes can stay inside and outside the mating ground, making it borderline impossible to escape alive if you are inside; on the other side, stumbling into a den is a death sentence because of the territorial and protective nature of drake mothers.