Circle of Crystals

Circle of Crystal druids first arose in subterranean environments, where they helped tend giant crystal gardens, but now they can be found almost anywhere with access to underground caverns or geothermal activity. These druids view crystals as a naturally occurring form of order and perfection, and they value crystal's slow growth cycle, as it reminds them the world moves gradually but eternally. This teaches young druids patience and assures elder druids their legacy will be carried on in each spire of crystal. As druids of this circle tend their crystals, they learn how to use the harmonic frequencies of different crystals to create a variety of effects, including storing magic. 

Resonant Crystal

When you choose this circle at 2rd level, you learn to create a special crystal that can take on different harmonic frequencies and properties, It is a tiny object and can serve as a spellcasting focus for your druid spells. As a bonus action, you can cause the crystal to shed a bright light in a 10-foot radius and dim light for additional 10 feet. You can End the Light as a bonus Action.

Whenever you finish a long rest, you can attune your crystal to one of the following harmonic frequencies. The crystal can only have one harmonic frequency at one time, and you gain the listed benefit while you are wearing or carrying the crystal. The crystal retains the chosen frequency until you finish a long rest. 

• Clarity. You have Advantage on saving throws against being charmed or frightened.
• Cleansing. You have advantage in saving throws against being poisoned, and you have resistance to poison damage.
• Focus. You have advantage on constitution saving throws that make you maintain concentration on a spell when you take damage.
• Healing. When you cast a spell of 1st level or higher that restores hit points to a creature, the creature regains additional hit points equal to your proficiency bonus.
• Vitality. Whenever you cast a spell of 1st level or higher using the resonant crystal as your focus one creature of your choice that you can see within 30 feet of you gains temporary hit points equal to twice your proficiency bonus, the temporary hit points last for 1 minute.

To create or replace a lost resonant crystal, you must perform a 1 hour long ceremony. This ceremony can be performed during a short or long rest, and it destroys the previous crystal, if one existed. If a previous crystal had a harmonic frequency, the new crystal has that frequency unless you make the new crystal during a long rest. 

Child of Stone

Whilst you are wearing or carrying your resonant crystal you ignore difficult terrain caused by earth, stone, mud, rocks, and sand.

Crystalline Skin

Starting at 6th level, when you take damage, you can use your reaction to cause your skin to become crystalline until the end of your next turn. While your skin is crystalline, you have resistance to cold damage, radiant damage and bludgeoning, piercing and slashing damage from non magical attacks, including the triggering damage if it is the appropriate type. You choose the exact color and appearance of the crystalline skin.

You can use this feature a number of times equal to your proficiency bonus. You regain all expended uses when you finish a long rest.

Magical Resonance

At 10th level, you can draw on stored magical energy in your resonant crystal to restore some of your spent magic. While wearing or carrying the crystal, you can use your bonus action to recover one expended spell slot of 3rd level or lower. If you do so, you can benefit from the resonant crystal's harmonic frequency for 1 minute. Once you use this feature you cant use it again until you finish a long rest. 

Crystalline Form

At 14th level, as a bonus action while wearing or carrying your resonant crystal, you can expend one use of your wildshape feature to assume a crystalline form instead of transforming into a beast. You gain the following benefits while in this form.

• You have resistance to cold damage, radiant damage and bludgeoning, piercing and slashing damage from non magical attacks.
• You have advantage on saving throws against spells and other magical effects.
• Your resonant crystal pulses with power providing you with the benefits of all five harmonic frequencies. When you cast a spell of 1st level or higher you can choose to activate only the healing or vitality harmonic frequencies or both, if you activate both you can choose two different targets or the same target. 

This feature lasts for 1 minute. or until you dismiss it as a bonus action.