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We may have found a material that may aid us in developing the city. Deep in the mines under Tvintiir we have found a new material, a crystal as black as night yet that has a faint interior glow. We think that this gem can be mined as a power source. If we can find a way to harness the energy many doors may be opened.

Missive of mine master Eldorshorts
1947 AC

The first recorded use of a coal-gem to power an artefact is from 1948 AC within Tvintiir. The gem in question, an unrefined and crude production, successfully lit a lamp for a span of nearly two minutes. This helped prove the capabilities of the material and led to the categorization and development of coal-gems into a science that proved critical to the Tvintiir State's defenses and city life for over 300 years before the Fall of Tvintiir in 2325 AC. It was only at this point that the darker side of the Coal-gem was discovered.

Mining and acquisition

Coal-gems are the most interesting development in lithic technology within the last 500 years.

Lithics, Gems, and Lodes –
Minerals and how to mine them

by E. Prof. Durntledon

Coal-gems are generally found in bands or veins deep beneath the earth, almost into the first layer of the underworld. The positioning of the veins do not seem to coincide with any natural phenomenon and the largest known deposits are beneath Tvintiir.

The raw gem appears like coal with lots of iron, coal, and stone impurities. The individual segments in the veins have, on occasion, been found to have humanoid or similar shapes but interlocking sheets of the gems are a more normal configuration. Once the gems have been refined though they gains a sheen and shape much like a diamond and shows signs of being highly pressurized. This has led to the belief that, like coal, coal-gems are formed in some way from organic materials that have been subjected to high pressure and chaos magic.

Due to the power within coal-gems, intense care is needed in mining them. The initial stage needs to be conducted in anti-magic spheres to keep them from imploding when being accidentally hit with a pick or hammer. It has been found that coal-iron picks and brushes have the least chance of reacting with the gems and normal iron causes ruptures to easily.
by Dario Brönnimann

After the gem has been mined, they need to be sculpted to get to the pure inner elements, the part of the gem that is fine enough to be mistaken for a diamond. Wards are also placed on the gems to both contain their power and protect them from accidental harm.

Show Spoiler

Coal-gem Classification: reproduction and improvement upon Nuungraltyby’s design

by E. Prof. Durntledon

Coal-gems are classified based on their size and quality. Six difference size categories and six different quality categories have been theorized, although not all of them have known examples. The power of a coal-gem is measured in Nuuns. See the tables below.

Rarity on scale 1-10. 1 = common, 10 = one of a kind
* At least figures. The full power potential has never been reached. It almost seems capable of recharging. Averages based on extensive LTA archives.


Uses for coal-gems

The power of the coal-gems have opened the doors (sometimes literally) for a host of different mundane and magical devices to be created. In all of them, the power of the gem is channeled to have a specific result within the object. In the following chapters, the different variants of this power shall be covered and...

Opening chapter of Coal-Gem Engineering:
Powering Artefacts and Channeling Power

Mundane items

There are a variety of more mundane items that coal-gems have been able to replicate. These items are low power objects, generally only requiring 10 or less Nuuns to work for extended periods of time. They tend to replace objects that are normally thought of as mundane, such as torches or compasses. Examples include: lamps/flashlights, 'candles', stones of cooking, the north homing, etcetera. The gems have also been used as fuel for furnaces and other such implements, capable of heating fires to far greater (or cooler) temperatures than ordinary fuels.
by Arimel through Midjourney

Substances / one use items

The coal-gem has been proven to have several different effects when ground down and powdered. This has led to experimentation when it is added to food or projectiles. The powder seems to have strong magic dampening effects or even be lethal when injected in the right amounts. Examples include: glitter stones, coal-poison , explosive gems, magic dampener salve, etcetera.

Magical artefacts

Coal-gems have also been used to power smaller artefacts, giving them heightened powers for limited periods of time. The gems in this case work almost like batteries, being able to replaced when the energy of the gem runs out. Example artefacts include: artificer's monocle, scrying shard, spell sink scarabs, periapt of warning, stone of messaging, etcetera.



The elemental and necrotic energy stored within coal-gems has also been utilized. The stones, depending on their size and purity, can be devised to release cold, electric, fire, or necrotic damage under select circumstances (such as, being smashed or successfully landing an attack). They can also be used to power magical defenses. Tvintiir has used this to great effect in designing their power armor, robotic suits that enhance the physical qualities of the defender and give them additional means of attacking.

The types of weapons and armor fueled by coal-gems tend to vary in power depending on the purity of the coal-gem used, with simple bonused being available for low power coal-gems while substantial bonuses are available for gems with more power.
The types of weapons include those that can deal energy damage, blood feeding weapons, retribution armor, or short term force fields.

Large scale projects and components

Finally, coal-gems have been utilized in powering much larger objects. These generally require gems capable of at least 100 Nuuns and the amounts of power drawn by the devices often consumes most gems in short periods of time. As such, the most desired gems in these circumstances are those that have the ability to recharge. These gems have been used for powering airships, carriages, and enhanced ballista and siege engines. Tvintiir also used them to power lighting and utilities for the entire city.
by Arimel through Midjourney


The source of coal-gems and magic

Having first seen this material, the so-called 'Coal-gem', I must say that great care needs to be taken. The gem itself radiates necrotic energy. This indicates that the gem has great potential either for taking or giving life. Until we can be sure which effect the gem will have on those around it I think it is safer to keep them isolated from the populace.

Excerpt from a letter from
Father Ignolia to Senator Lighthearth

Coal-gems have strong magical potential. They radiate necrotic magic and react when they come into contact with magic. Spells cast onto the gem feed them extra power and deaden their effects. Some have even said that the gems even contain personalities or wills of their own. Only a few know the real truth behind this.

Only in 2325 AC was the real power source of the coal-gems revealed, them being capsules holding the lingering souls of beings of the ancient past. Many of the souls were torn beyond repair, the gems being produced being weak and flawed. However, the stronger willed or most perseverant of souls could maintain their sense of selves or absorb those of others around them. These gems have been known to be able to use their inner power to influence their surrounding worlds. The strongest one known, the self-called Ancient King, was the architect being the fall of Tvintiir and the presence behind the Cult of the Black Bones. While a couple of the spirits within the gems have been found to have good intentions for the living, most of the spirits seem to be monovalent. They have clung on past their time to life and will do whatever needs be to regain physicality, even at the expense of the living.
by Arimel through Midjourney

After Tvintiir fell and this knowledge became more widespread the use of coal-gems diminished, largely due to the work of Flimp Anthane McBlarn. Through her persistence the detrimental effects of coal-gems on sorcerers and the dark powers behind them ensured them to fall into history.


Coal-gems and sorcery

Sorcerers have an innate link to magic. This link provides them access to the powers that they harness but it also makes them vulnerable to many of the more magical threats. It is through this link that spirits within the coal-gems can reach out to the sorcerer. It is through this link that, ultimately, the spirit gains a chance at the victim's soul.

The storm within us – Compilations of
the writing of Chimpanee Triff McBlarn

by F. A. McBlarn

The power a coal-gem exerts over its surroundings is particularly strong for those with significant amounts of innate magic. Sorcerers are especially vulnerable to this. While they may be able to be near the smallest of gems, the larger variants and the purer gems can affect sorcerers even from vast distances of up to 20 feet. The longer the sorcerer is in proximity to the gems the more susceptible they become. It has also been noticed that the more powerful the magic user is, the more difficult they find it to resist the effects of the gems.

While some may say that the effects of the gems are harmless, the negative qualities of the gems on sorcerers and those around them can be extremely destructive. Some effects involve madness, visions of the ancient past, draining of energy and life, explosions of energy, and super-powering of artefacts. While these may be bad in their own right, the worst results of coal-gems could include the spirit within the gem being set free or even switching places with the soul of the sorcerer themselves, forever trapping the sorcerer's soul within the gem. Many of these effects can result in the death of the sorcerer or those around them.

There are a couple of ways to reduce the effects of the coal-gem on sorcerers. Being in areas that have negated magical presences,
by Arimel through Midjourney
such as, antimagic fields, tend to prevent the connection between the sorcerer and the gem. However, there are a couple of other methods including dampening the magic of the individual. There are several different amulet patterns that can be used to limit the wearers magical capabilities and reduce the impact the gems have over them. Overall though, all of the solutions require dampening or withholding the sorcerer's power. There is no known solution to prevent the soul within the gem from reaching out without destroying it, an action that could have equally destructive consequences.

Coal-gem illnesses

It has come to my attention that many of the sorcerers that have recently been found in the city are all related to the mining families. As such, we need to increase our checks on their offspring to ensure they do not have the opportunity to cause havoc in the city.

Letter from Professor Durntleton
to Captain Entillygent

From the earliest of times, it was known that coal-gems had a negative effect on those around them. Coal-gem miners were the first to experience its power, going slowly mad in long proximity to them and other scientists were the next to follow. These cases were hushed up and extra safeguards put in place surrounding the gems. The refining of the gem and wards placed over them help to reduce the average touch to those nearby. However, these haven't fully gotten rid of the effects of the gems. Overtime, those in long proximity with the gems can still feel drained or weakened and there is a pattern of sorcerers being born into these families.
Jet black
Common State
Related Locations
Settlement | Oct 31, 2022

The Original Library of Technological Advances
Organization | Sep 30, 2022

Cult of the Black Bones
Organization | May 7, 2023

Character | Sep 27, 2022


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