Commission by *Siansaar, featuring the Changelings original form.
Known as the Shahbanu (female Shah, which translates to "Queen of Queens"), this unnamed Changeling is heavily based off the Indian Southeast-Asian culture (so this is India, not Native American Indians!). Now there are some people who say these are... flutterponies or something from G1 or a corruption of the Changeling...? I haven't read any of those ideas but this is something I just came up with on my own, so this is my take on it.
Being that India is a very spiritual and cultured people, I came up with the idea of these 'Crystalline' creatures by basing their beliefs off Hindu-ism and Buddhism (both predominant religions of and near India). Long ago, the Changelings were a single great empire, capable of amazing advancement and solidarity.
One day, they discovered the 'power of love' and a great debate broke out on how to best harness and utilize this raw source of power. One faction (the Black Changelings) promoted the idea of 'taking it by force', while the other (the White Crystallines) side thought that was unreliable and dangerous and advocated 'self love'. A civil war broke out which saw Queen Chrysalis Changelings expelled from the Raj, never to return.
During their banishments, the Changelings (using force and being all dark-like) began to become twisted and corrupted, changing into the current beings that they are now: able to take the form of others and looking like Swiss-cheese!
The Crystallines, however, went head-first into the idea of self-love - becoming narcissistic creatures who value their well-being over all others. They became more 'beautiful' than their twisted Changeling counterpart; taking on lithe and sleek white bodies though if one looks closely they can see the past semblance between their distant others. What sets them the most apart is their abilities are much like the Mesmers of Guild Wars 2. While Changelings can change their own forms, the Crystallines use 'illusions' to project hallucinations over those they have a grudge against, confounding them in their memories and tormenting them without ever getting their hooves dirty.
They also are huge lovers of 'mirrors', hence their affinity for crystals and polished rocks and sparkling minerals. The 'Crystalline Raj' is an isolationist nation and has thus far been keen to avoid entangling itself with much of Equestria, though all that is about to change when a certain group of Crusaders stumbles upon their territories...