Spell Gem

Gemstones imbued with the power to absorb and re-expel magic and spells, Spell Gems are as valuable as they are rare.
Only found as product of the Silver College in Shacklegorscht, it is uncommon to find them in the Underdark and extremely rare to see them on the surface.

The function of such gems were to store single spells. Specific types of gems could store more powerful spells. Unlike typical spells or scrolls, anyone could cast a spell stored in a spell gem. However, the more powerful the spell stored was, the more difficult it was to cast it. The whole creation process is a closely guarded secret by the Svirfnebli of the Silver College.

Variations

There were several types of gems that could store spells. In order of the power of spells they could store, the gems were:
Obsidian (cantrips only)
Quartz (Up to Level 1)
Sapphire (Up to Level 2)
Bloodstone (Up to Level 3)
Amber (Up to Level 4)
Jade (Up to Level 5)
Topaz (Up to Level 6)
Amethyst (Up to Level 7)
Ruby (Up to Level 8)
Diamond (Up to Level 9)

Item type

Power Storage / Generator