Gems

Diamonds, rubies and emeralds: where they come from, where you store them, what you need them for and how to turn them into gold in your main castle.

There are three gems: diamond, ruby and emerald. Each castle mines exactly one kind – which one is fixed by its location; the construction wagon map shows the gem type of every free field (Construction wagon). Gems belong to their castle and are kept in its Treasury.

Mining

A castle only starts mining gems once you have researched the advanced research "Mine gems" there (Advanced research); every level raises the amount. More comes from the field's gem stars, premium mini packages, the Healer alliance specialisation, the "+25% gem bonus" amber blessing and the laboratory milestones in special castles. Bandit camps also have gems among their stolen goods (Bandit camps).

The treasury

The Treasury holds your gems – the higher the level, the more. Once it is full ("Treasury filled to capacity"), newly mined gems are lost. More room comes from the Elite Trade master (+25%), from treasury extensions in Baldur's Fortresses and from purchases in some events.

What you need them for

Rubies pay for your construction wagons once your realm has grown larger (Construction wagon).
Emeralds buy deeds of conquest, which you need for every conquest once you own a certain number of castles (Conquest).
Diamonds give the best rate when turned into gold and the cheapest healing from the healers – who also accept every other gem (Healers: saving wounded troops).

Turning gems into gold

Only in your main castle does the advanced research "Philosopher's stone" turn gems into gold. Every research level lets you convert 1 more gold per month; with each new month the limit starts over. For 1 gold you need 50 diamonds, 400 rubies or 1,000 emeralds – the treasury shows the exchange rate.

Gem trade

In the market's Gem trade tab you send gems between your own castles – sending them to other players is not possible. The target castle needs a Treasury. The same traders as in direct trade carry them, and one gem counts like one unit of resources (Traders and routes). Whatever the target treasury cannot hold is lost – except on the Elite Trade master's gem routes, which bring the surplus back.