a rando furry

This species known as 'crystallized' are a species caused by humans being exposed to a force on a specific planet, this force causes tissue that dies (like how your cells are constantly dying and being replaced) to be replaced by crystal in a process named opalization, (named after how bones can be fossilized with opal rather than rock) flesh becoming a (typically transparent) gemstone type, while bones become a denser (usually opaque) gemstone, with fractures often having minerals around them such as gold and copper. Though in rare cases parts of or entire organs can be crystallized as well, though this is a rare thing

The individual depicted above has blue topaz 'flesh' with lapis lazuli bones

The process of opalization takes approximately 7 years and can happen to any organic animal, plants are effected differently, but humans are classified as a specific separate species (because of course they are) though the process can range from uncomfortable to outright painful, with the slowed, or even stopped, movement it causes in its earliest stages often causing extremities like hands and feet to mummify and eventually fall off, though they are replaced with crystal. The process also causes complete blindness, though crystallized can use the vibrations in their gemstone bodies to sense the world around them, this is a something that is learned with time though.

The crystal grows much like flesh does, though often adding features not native to the species a specimen is, typically horns and sometimes tails, though other growths are possible, simply rare or unobserved hypotheticals

The first person to be affected by the phenomenon (depicted above) was exiled to what was thought to be an uninhabited planet in an attempt to get around laws against the killing of someone aboard a ship (despite them being innocent of what they were accused of)