Elementite ("element stone") describes a class of gemstones believed to be able to contain a limited, calculable amount of 'elemental' forces. There are a great many types of elementite, each of them able to absorb a specific element and made of a different material and thus color; bloodstone for example absorbs and releases blood, topaz electricity, and so on. It is a type of enchanted gemstone in that peoples' beliefs that they absorb these energies gives it that property. The larger the elementite, the faster it can absorb or dispense their given element, and so the more powerful the effects that can be worked with it, and the more energy it can hold.
It is believed to be charged merely by being in contact with the element it can absorb, or in some cases (such as fire/heat, lightning, cold), being anywhere near the element. The larger the elementite, the more its "pull" on the element, such that say a pearl (a light elementite) can, if large enough, pull all light toward it, appearing as a black hole and distorting all the light around it, even darkening the vicinity.
This attractive property of elementite means that it can be worn on clothing to provide protection against their matching element, ie. any electric spell directed at a person wearing topaz will only charge up the topaz instead of striking skin and potentially causing injury.
Elementite can be slightly cracked to cause it to slowly release whatever energy it stores. Ie a slightly cracked pearl glows like a lamp, and will continue to do so until the light energy stored in it becomes depleted. During the day, then, the pearl will attract light toward it. Of course, once cracked the elementite can only be made whole again with magic.
Elementite can also be thrown as "gem bombs". As they are believed to be volatile, when they strike the ground they detonate, releasing all their pent up energy in a powerful blast. For example, a fire elementite can be thrown to cause a large fire blast. The elementite is shattered into many smaller pieces in the process, and all energy depleted from them. Of course, once shattered the elementite can only be made whole again with magic.
Elementite can be be harnessed in various spells of the matching element to empower them.