The Jewel of the Sea

As you wander the halls of Kharesh, you eventually find your way to the storied Hall of a Thousand Stories. The tapestries and carvings are colourful and vibrant, despite many being hundreds of years old. You marvel at the figures, although your rudimentary Weddic prevents you from reading the runes on them very well.
You come across one carving that is several hundred years old. It shows a great figure, made out of a swirling liquid, staggering backward into the ocean. On the shore is an equally tall figure, with dwarven features and shining silver armour. In its hand is a bright light, which points towards four smaller items.
One of the items you recognize from your visit to the mayor's estate here in Kharesh. It is a round gem, an aquamarine with flecks of gold inside it. When the dwarven diplomat you were travelling with met the Mayor of Kharesh, his office contained a similar gem set inside a necklace.
You eventually exit the hall, and you seek out the diplomat. In his carefully-practiced Common, he replies, "That is the Jewel of the Sea, the most prized possession of the dwarves of Kharesh. Or of anywhere, for that matter. The god Mordarin crafted it to help banish one of the Chained Ones, and then gave it to our race after the First War."
You are astounded that something from so long ago could not only survive that long, but still serve a use today. You wonder what will become of it in the centuries to come. Hopefully Tharis'ala stays under the ocean waves forever...

History

The Jewel of the Sea was one of the first items created by the patron god of the weddelar, Mordarin. He poured much of His strength into it, and planned to give it to His chosen people once His work was completed. However, He needed it much sooner than anticipated.
A goddess, whose name has long since been lost but is known as Tharis'ala, the Chained Ocean, had grown jealous of the gods. In her madness, she had created an object so immensely powerful that her creations would overshadow and destroy much of the world if they harnessed the object's power directly. Her and Tharis'duran, the Chained Fire (and Tharis'xar, the Chained Darkness if you believe she exists) were sentenced to be banished by the other gods, and her creations were destroyed.
To chain her, Mordarin crafted The Chains of Igneous Imprisonment to bind her, the Blade of the Dawn to focus the binding energy, and the Totem of the Healing Well to keep the chains from rusting or aging. Finally, using the power stored in the Jewel of the Sea, he trapped her deep beneath the waves, never to be seen again.
Following this, he entrusted the dwarves that would later settle Kharesh with the Jewel of the Sea, where it became their most trusted relic. The Jewel was carefully cut and placed within the Necklace of Kharesh, which has been worn by every king and mayor of that town ever since.

The items used in the Ritual of Banishment. The Jewel of the Sea is in the top right.

Item type

Unique Artifact

Current Location

Kharesh

Current Holder

Côrin Maciarth

Owning Organization

Clan Maciarth

Rarity

Unique

Weight

75g

Dimensions

about 5cm in diameter

Appearance

The jewel itself is a deep aquamarine, with a bluish-green colour and a round shape. Small flecks of shiny metal, gold in colour, are trapped within the crystal; this is believed to be how Mordarin stored some of His power in the gem. The gem is opaque, and magical senses would detect a large source of divine magic within it.

Art Credit: emperorcharlesii (me!)