Crystalhogs are considered adults when they stop growing larger, which is usually about half a year after they hatch. Adults are even more active than hatchlings, always exploring, and so it is both common for crystalhogs to be stumbled upon at strange places in the Keep, hunting a tasty insect, and for a magi's crystalhog companion to not be at the Keep at all. Adult calcite crystalhogs have a more potent focusing aura, and so it is not uncommon for a magi to attempt to keep one nearby during study or research. However, this is usually best accomplished by hiding a snack in the vicinity in a tricky spot, so that the crystalhog keeps attempting and failing to reach it. Calcite crystalhogs shed their gems continuously, one at a time, so in a pinch, if a calcite crystalhog can't be kept around effectively, one of their crystals will help with focus, though not as effectively.
Unlike their cousins, the gemhogs, crystalhogs are constantly in motion from the moment they hatch, so much so that there are legends that crystalhogs must stay in motion or their heart will stop. Such legends are easily disproven, though, as crystalhogs also startle easily, and are capable of being perfectly still when rolled up in a protective ball of crystal spikes. Crystalhogs are not particularly affectionate companions, being prickly in both demeanor and looks. They are always slightly grumpy to be called upon, usually requiring tasty bribes if a magi wishes to befriend one, but when startled, the eyes peeking out from the spiky bundle look downright reproachful. Like their gemhog cousins though, crystalhogs are excellent pathfinders - and in the case of calcite crystalhogs, this literal skill also confers metaphorical prowess to those around them. Therefore calcite crystalhogs are often used both to find the shortest route home from a place, and also to help aspiring scholars focus their mental efforts. Oddly, despite this power, they themselves are not the brightest of companions, and it is not an uncommon sight to see a calcite crystalhog attempting to solve some puzzle or other by repeatedly trying the same thing over and over again despite a lack of success.
Sprite art: Munin | Description: Kestrad