Silver

An upgrade to all your Earth based abilities allowing you to turn things to gold has a different effect on different powers. 

Mould Earth: You can double the Resource to turn your mould Earth to silver, rolling a light attack to restrain people.

Throw Rocks: If not already silver you can use an extra Resource to turn the rock to silver causing it to be a Light attack & deal Celestial damage.

Stone Armour: For three resources you can make your Armour silver, giving all your martial attacks Celestial damage while the armour is up.

Turn Stone: For free you can flavour your body as silver.

Golem: For 3 more Resources you can turn your Golem to silver making all their attacks to Light attacks and deal Celestial damage.

Petrification: You can freely turn someone to Silver for flavour.