In areas of the world where the boundaries between the material plane and those of the elemental planes grow weakened, or in some cases even break, the resulting mixture of pure elemental energy and the natural world creates materials with extraordinary traits. Each crystal type has its own traits and features, and elemental crystals as a whole share few unifying traits outside of their otherworldly origins.
Aside from their sustainable uses all elemental crystals can be released of their power through arcane contraptions that siphon off the pure energy that they house, to be used as fuel for many different purposes.
Air crystals have no weight and are almost completely transparent if polished, easily mistaken for diamond until a basic inspection is done . Their color varies with purity of the stone, ranging from a medium blue to nearly colorless. When an air crystal is being held and is released, it never falls. Both the size and weight of the crystal determine the weight it can hold without falling.
Air crystals are extremely crystalline, extremely brittle and only workable by hammer and chisel. Its notoriously difficult to sculpt air crystals with precision, so items of detail (such as clockwork items or most armors) are rarely (if ever) constructed from air crystals.
Air crystals of extremely minor purity are often used for decorations; artisans will inlay precious metals or gemstones into the crystals and sell them as free-hanging art pieces for those who can afford them. These art objects range from extremely cheap (such as a palm-sized crystal wound in copper wire) to extremely expensive (a finely carved crystal chair with intricate gold and silver designs covering the majority of its body) but never have any use past simple aesthetic pleasure. Crystals of increasing purity, however, tend to have more practical uses. Greater crystals are often used in the creation of air-related magic items to create effects of greater intensity, while extremely pure crystals are an essential part of any airship that expects to travel anywhere.
Fire crystals are have more in common with metals than crystals and are universally warm to the touch, sharing most other qualities with copper. They’re smoky and opaque, their color ranging from a rusty brown to a bright, flickering orange.
Due to its soft structure, fire crystals being formed into weapons or armor is almost unheard of; Their most common use is in the day-to-day. An extremely wealthy merchant might commission a sheet of fire crystal for his bed to lay on, forever ensuring him to never deal with an uncomfortably cold night again. Fire crystals of high purity are dangerous due to the temperature they exude, as they can quickly ignite things that they come in contact with (and in the case of extremely pure crystals, sometimes only proximity is enough for ignition); thankfully this trait also makes them extremely difficult to house or smuggle. However, there are some (few, but some) practical uses for more pure fire crystals… the heat they exude has amazing uses in crafstmanship and this items forged in their heat are also of higher quality than those made with more earthly flames.
Earth crystals are heavy, multifaceted, brittle crystals that are usually green in color, though brown is not unheard of. When crushed into dust and sprinkled onto fields, they are used to promote fertility within soil. [to be expanded later]
Water crystals are smooth, translucent stones that continually look and feel wet. Their coloration is always blue, though all shades seem to be reported with equal frequency. [to be expanded later]