Felt inspired to create this racial/species option based off of a desire for a) more non-Humanoid races and b) more unique mechanics. Let me know what you think

Corunda

The Corunda are a race of gem-like creatures native to the elemental plane of Earth. Their bodies are usually not “born” as they are formed over long periods of time from the various minerals and metals present in their homeland. Very few will traverse to the Material Plane, and many who do wander there by mistake. 

Ability Score Increase

Increase one of your ability scores by 2 and another by 1. 

Age

Corunda are naturally ageless, potentially able to live for a millenia; however, such extended lifetimes often require one to remain in solitude and away from danger. The lifespan of a Corundan is naturally reduced by cracks that form over time on their bodies. One pursuing the rugged life of adventuring will likely live for around 90 years. 

Appearance

Corunda are sometimes mistaken for celestial beings, as their bodies have a brilliant crystal shine to them. They can come in nearly any color, from sapphire blues, to ruby reds, to emerald greens - some are even translucent and lack color. In Corundan society, the clarity of one's body is considered to be linked to both physical and spiritual purity. Those who can obtain the most brilliant shine and clarity will generally be accepted into leadership roles within their groups. 

Languages

You speak Common and one other language of your choice.

Creature Type

You are an Elemental

Size

Your size is Small or Medium. You choose this when you select this race.

Speed

Your base walking speed is 25 feet

Brilliant Body

Your crystalline body infused with your living essence can be as precious as gemstones. If you (or a friendly creature within your reach) casts a spell which has a gem as a material component, your body can potentially be used in place of that component. For this purpose, your body can replace any type of gemstone and is treated as having a gold piece value equal to 100 x your Proficiency Bonus. If the replaced gem would be consumed by the spell, immediately after it is cast you must roll a number of your Hit Dice equal to twice the spell’s level, taking force damage equal to the value rolled, which cannot be reduced in any way. 

Additionally, if you die, your body is immediately reduced to a fine powder which has a gold piece value of 100 x your level. 

Crystalline Defense

Your hardened body helps to stave off damage. You have a Damage Threshold equal to twice your Proficiency Bonus. Any damage from a single attack or effect that fails to meet or exceed your Damage Threshold is considered superficial and doesn’t reduce your hit points.

Whenever you take the Dodge action, your Damage Threshold is doubled until the start of your next turn.