Obsidian

Obsidian (OB) is a reagent that is in use on Pagan. This dark stone, while often used for decorative uses, has proven to to be very useful in the arcane arts as well.

Pagan
For the magic school of Sorcery, obsidian proved to be an ideal reagent to add duration to a spell, since due to its nature, it can endure the heat of a volcano without much ill effect. This is little wonder, as it is created from fast cooling lava that has only a small water content in it.

Trivia

 * Technically spoken, obsidian and pumice are almost the same, the difference just being the amount of water and the time it takes the lava to cool down.