Stone Domain

Stone domain clerics worship gods of the earth, such as Geb. They adorn themselves in raw stones, metal ore, and crystals, as a show of their devotion to these gods. These clerics tend to be stoic and laconic. They are charged with the protection of the physical earth itself from societies that wish to exploit it. They are often employed by mining companies to help them safely locate large mineral deposits in a way that least damages the infrastructure of the caverns.

Natural Armor

When you choose this domain at 1st level, your body is fortified by the earth. You gain a +1 bonus to your AC.

Earthblood

Also starting at 1st level, you know the Mold Earth cantrip, and it counts as a cleric cantrip for you. You also have double proficiency on all Investigation, Perception, Nature, and Survival checks specifically relating to caverns, mineral deposits, or other rock formations.

Channel Divinity: Crystal Form

Starting at 2nd level, you can use your Channel Divinity to physically emulate the earth.

As an action, you present your holy symbol and transform your body into limestone and crystal. You maintain your humanoid form, but your appearance and body composition changes. This transformation lasts for 1 minute or until you dismiss it and has the following effects:

You gain a +1 bonus to your AC and a +1 bonus to your constitution modifier.

You become proficient in Constitution saving throws against everything but acid damage. If you are already proficient, you become doubly proficient.

You become resistant to bludgeoning, slashing, and piercing damage.

Your speed drops to 10 feet.

Rocky Terrain

Beginning at 6th level, you can alter the terrain around you at will. Choose a 30 foot square area anywhere within 120 feet of you. Sharp rocks jut up from the ground in that area, turning it into magical difficult terrain. In addition, if an enemy is knocked prone in this area, they suffer 2d6 magical slashing damage. This damage increases by 1d6 at 12th level (3d6) and again at 18th level (4d6).

Divine Strike

At 8th level, you gain the ability to infuse stone with divine energy. Once on each of your turns when you hit a creature with rocks, you can cause the attack to deal an extra 1d8 magical bludgeoning damage to the target. When you reach 14th level, the extra damage increases to 2d8.

Cave-In

Starting at 17th level, you master your control over stone. As an action, you can cause large boulders to fall in up to a 20 foot square of your choice, anywhere within 60 feet of you. All creatures in the affected area are knocked prone and suffer 10d10 magical bludgeoning damage. Affected creatures must also attempt a Constitution saving throw. On a failed save, they are knocked unconscious for 1 minute or until someone uses an action to wake them up.

You can only use this ability once per long rest.