Gems

Gems come in four flavors, and have no base use, but each can be a tasty magical condiment for your salad of power.

Types of gems
Rubies are associated with fire.

Sapphires are associated with cold.

Emeralds are associated with acid.

Topaz are associated with lightning.

Gem uses
Gems can be mixed with amulets to provide a resistance to the associated element.

Gems can be mixed with a Potion of Absorption for an appropriate potion of resistance.

Gems can be charged with a potion of energy and attached to your staff to make an element attack, note below how you can't charge with a fountain.

Gems and fountains
Dropping a gem changes the fountain's flavor, while leaving the remaining charges intact.

Rubies change it into a healing fountain.

Sapphires change it into a fountain of change.

Emeralds change it into a fountain of inversion. This is the only one which doesn't match the color of the water.

Topaz change it into an energy fountain.

Dropping a gem on a fountain of its own flavor has no effect, and the gem is not lost.

As a side effect, you cannot use a fountain to charge a gem, even a topaz.

Gems and Tokens
Mixing a Gem and a Token of Ath will create the corresponding Fountain.

Mixing a Gem and a Token of Sateja will prompt for a direction, then create a Ball 6 area of special terrain. Mixing a Gem and a Token of Laxuno will create a Rune on a nearby tile of a type related to the Gem's element.
 * Rubies ► Lava
 * Sapphires ► Ice
 * Emeralds ► Acid
 * Topaz ►Water, strangely enough.