Storm crystals are rare crystals often found in small cluster formations in the high-elevation mountain regions of Tarias. They are usually clear and prismatic, with a slight blue tinting often resembling that of the rare blue diamond. However, unlike the diamond, these stones have a useful and potentially deadly property.

These crystals are so named because they are always found in regions prone to violent lightning storms. The reason for this has to do with the crystals themselves. The crystals have a natural tendency to accumulate and release electrical charges. This not only makes them prime targets for lightning strikes, but far more often, the crystals are the source of the lightning discharges.

Cultivating such natural wonders is a dangerous, but rewarding enterprise. The amount of electrical energy stored in a crystal no larger than a man's finger is enough to kill him should it suddenly discharge, and the smallest spark can set off a fully-charged crystal. However, when successfully cultivated and employed with the use of magic, storm crystals can create a potent weapon or energy source. As such, they are often found in magical staffs, wands, and powerful spells.

Because their energy capacity varies from one crystal to another, based in part on size and amount of imperfections in the crystal, the power and value of storm crystals are based on the number of "charges" they can hold. Devices which employ these crystals can use these charges to perform specific functions, deal damage, etc. Either way, the function or damage is always electrical in nature. The typical value of a raw storm crystal varies widely. The value starts at 100gp per charge, but then increases 25gp for every additional charge the crystal can hold. Thus a crystal that can hold 2 charges is valued at 250gp (125gp per charge), and one that can hold 10 charges is valued at 3250gp (325gp per charge). A crystal that can hold 20 charges is valued at about 11,500gp.

In terms of damage, a single charge in an unmodified storm crystal can deal 1d6 points of electrical damage to all targets up to 5' away, or a single target up to 5 yards away. Two charges can deal 2d6 points to all targets up to 10' away (or a single target up to 10 yards away), and so on. When discharging naturally, they can discharge any number of charges at once, up to the number of charges currently stored. All targets may make a save vs. electricity (5 or less charges) or lightning (6 or more charges) for half damage.

Magical devices, such as wands and staffs, can dramatically increase the range, area, or damage of the discharge by controlling and focusing the release of energy for a specific purpose.

After discharging, storm crystals naturally recharge over time (1 charge per day), but the process can be expedited through magical means. Care must always be taken, as the crystals have a nasty tendency to discharge if they are charged too much or too rapidly. To recharge a crystal, electrical-based damage spells may be cast into them. 1 charge is added to the crystal for every 6 points of electrical "damage" the spell inflicts on the crystal. However, there is a chance that the crystal will discharge, based on how full the crystal is when the spell is cast. The following is a rough guideline of the chances of a discharge after charging it with a spell:

10% full = 1%
20% full = 4%
30% full = 9%
40% full = 16%
50% full = 25%
60% full = 36%
70% full = 49%
80% full = 64%
90% full = 81%