Arcanum Crystal

Arcanum crystal is the only material yet discovered that will allow magic to affect physical states in an ongoing fashion, rather like a programmable battery. Arcanum is actually a classification of several types of crystal, but only those trained to manipulate the crystal can tell the difference. Prior to magic being applied, there is a slight aura of magic to the crystals, but only something those who can use magic are able to sense. Some have described it as a vibration, others as a tingle on their skin when they approach. To the average person, there is only one kind of arcanum crystal, and it's the one being actively used in magical applications.
Table of Contents

Physical Characteristics

The crystal appears in a variety of colors and shapes, though it's typically clear and favors six-sided prisms with pyramidal ends. It is very similar to common rock crystal or quartz in many ways, though arcanum crystal's obvious magical applications make it hard to tell if there are any similarities in origin between arcanum and quartz. Like quartz, it is next to impossible to burn, melt, or otherwise apply heat to change the state of the crystal. The melting point is higher than common ability to burn, including common smith's forges. (Roughly 1700°C.) Magic can produce the heat, but most magic users have little value for melted arcanum.
The color variations do not seem to be significant in determining which arcanum crystals are useful for what purpose, and it's common to see any number of slight variations in color in even the same types of magical instrument. It has been hypothesized by merchants who sell such magitech that the rare lavender color is sought after for more than just the visual appeal, but if this is so, the mages who work the crystal aren't telling.
Once magic has been applied, the physical characteristics of the crystal change relative to what type of magic, so it is impossible to give a ready description. Some types of magic do have a scent, which surrounds the crystals they're worked on. Unless the crystal glows or shows obvious signs of having active magic, it is unlikely the lay person can tell the difference between natural arcanum and worked arcanum.

Occurrence

As the name suggests, arcanum crystal is a crystalline solid. Like quartz, it can be found in veins or layers in granite, sandstone and shale, and other layered rocks. It is unlikely to have been in places that would allow it to become part of sedimentary soil or stream sediment, but due to its similarity to quartz, the possibility is there.

Mining

Like quartz, arcanum is extracted from open pit mines, where the veins are exposed and then worked with hand tools. The crystal veins commonly become twisted and must be followed with either magical blasting of the waste rock or tunneling by hand. Magical blasting is used as a last resort, as abrupt temperature changes can damage the crystal. Aside from the safety precautions necessary for those chipping at the crystal, arcanum is not known to affect miners or cause any medical problems for those handling it.

Safety

When working with arcanum crystal, protective equipment must be used to avoid inhaling hazardous levels of crystalline dust particles. Cutting, drilling, chipping, sanding, and even polishing crystal can produce the dust immediately. Cloth face protection is not enough, though several layers have been used with minimal intake of dust in a single working session. A single working session without adequate protection is enough to cause diseases of the lungs, with nasal passages and oral tissues at risk as well.

History

The discovery of arcanum crystal a little more than a hundred years ago was the turning point for a magical-technology revolution changing all walks of life. From lamps that never die to making large mill stones turn with ease, each new invention has improved the quality of life for everyone. Until this era, it was unlikely that any family unit could completely specialize in a trade or craft, needing to spend significant portions of time maintaining shelter and processing foodstuffs. With the new inventions available, families are now able to focus on their craft, trading their specialization for grain milled in large quantities, cloth and leather processed more rapidly, and so forth. The era is yet new, only a century old, and inventions continue apace. The quality of life for everyone from commoners to kings is anticipated to continue to improve likewise.

Deterioration

Arcanum crystal can hold magic for a long time, based on two factors: the type of magic and the amount of power provided for it. The simplest magics, such as when the crystal is used as a light source, will last several lifetimes. The stronger the magic, the faster the crystal's power supply will be used. The more complicated the magic likewise. While a power supply can be refilled to a lesser extent with successive renewals, the crystal has a finite limit to how long it can process the magic, regardless of power provided. Excess power remaining at the time of full deterioration can cause unfortunate effects, up to and including magical explosion.
Some arcanum professionals have attempted to exchange what magic is in the crystal once it starts decaying, such as taking a complex mechanical device and turning the crystal into shards for light, which will last far longer than the mechanics might have, however the crystal, once deterioration has started, will continue to do so. Progress on this front has helped when stores of arcanum were low, but the mixed results haven't led to any conclusive answers.
Deteriorated arcanum can still be used in many of the ways that common quartz may be, though it is slightly more brittle and the tensile strength of the crystal is not up to the standard of most quartz. The deteriorated crystal may look the same as it always did, cloud slightly, or outright blacken.

Material Type
Mineral, potentially Magical

Purpose/Uses
Magical technology

State
Crystalline solid

Color
Varies. Typically clear, different mineral occlusions can cause faint color, most commonly white/cloudy, pink, and yellow, though green-blue is possible, and the rarest lavender is highly sought after for visual appeal.

Value
Natural crystal is valued between X and Y gold pieces. Once used in magical applications, the value increases exponentially. Deteriorated arcanum is valued based upon its remaining potential use.