This is an Orange gem in the shape of a pyramid. Various symbols are engraved into it. Underneath, there is a fine carving resembeleing a bird. A set of armor is stored inside of it. Sets of armor can be stored / extracted by using a jewelry kit on it. This can be done at the end of a Short/Long rest. The armor is deployed by breaking the gem. The user will be encased in crystal armor, which reflects the stats of the armor infused in the gem. At will, the wielder may return the armor into the form of the gem.
If used this way, the user gains several benefits: The user will grow one size as the crystalline armor surrounds them. They may also ignore the disadvantage on stealth checks if the armor usually imposes it. If the used armor is the Armorers 'Arcane Armor', the user may also exchange one attack of the extra attack with a cantrip. Additionally, changing the type of the armor (Guardian/Infiltrator) can now be done in a 10 minute ritual instead of a Short/Long rest.