Dwarven Earthcasters

Within Dwarven culture there's many professions that grant prestige as well as coin, but none are respected more than the Earthcasters. While other dwarves will gild their armour and weapons in silver, gold, platinum and gems, the Earthcasters can habitually be seen in plain brown robes with a single band of some form of metal around their upper arms. The specific material of these bands denotes the ???, similar to a military rank. The Earthcasters are a combination of spiritual advisor, military strategist, and political power.
Copper is the lowest rank within the Earthcasters, known as a 'Burnished' and most that are found in smaller villages or working under an Earthcaster of higher rank within a temple in larger cities. Burnished can sway a burgomeister or elected official of these smaller villages.
Silver bands show that this dwarf has attained the rank of the 'Polished'. They have been a member of the Earthcasters for at least 50 years, and can be found leading congregations of a few thousand dwarves. They normally have a few Burnished working with them to assist in their work. They cannot command nobles, but can overturn smaller court's decisions, and command a military squad of ten dwarves.
Gold bands are generally more rare, only appearing as a few within larger cities, and habitually are dwarves that are well into their second century. 'Gilded' is the term they're recognised by, and can overturn higher courts decisions. They habitually are not seen outside of their temples unless the feel their need is great.
Platinum 'Honoured' are not seen outside of the great capital. These special few are second only in power to the emperor, and can command unquestioning obedience from the nobles surrounding the Hammerbearer. Honoured rarely interfere in politics, more concerned with the collating and administration of the Earthcasters throughout the empire.
Earthcasters are only ever chosen by existing Earthcasters. It's not an order that will accept volunteers, rather deciding who they will include by some unknown criteria.
There are rumours that there is even a rank above the Honoured, for those that exceed the platinum band, but none have ever been seen.