Due to your durable crystalline body and positively reflective personality(if someone positive is who you're talking to), your Constitution increases by 2 and Charisma increases by 1.

Due to your crystalline body's reflective surface, spells with radiant damage will have disadvantage against you, though you will still be blinded. If attacked at long range, you are able to reflect the attack back at the aggressor or one other enemy close within the general direction you're facing up to 120 feet away with the same damage roll before blindness takes effect. Make a constitution save to get rid of the blindness until you succeed.

Due to the molecular structure of your body, resembling that of diamond, you pose disadvantage on physical attacks and spells with bludgeoning and force damage. For spells it's up to and including 4th level spells and physical strikes will always have disadvantage against you, magical or not via spells or racial traits. You even have immunity to force or bludgeoning cantrips and level 1 spells. However, it's the same molecular structure that will fail you against finesse based attacks, so you're vulnerable to slashing and piercing damage.