Gems

A gem is not mere wealth; its crystal lattice is ordered matter, which holds magic the way a vessel holds water. For magical rituals, a gem is fuel.

Size, Quality, & Affinity

A gem's value measures its size and purity and its capacity to hold magic. The value is not necessarily a measure of what the gem could be bought and sold for, but it does determine potency in magical crafting.

Every gem can fuel magic, but each resonates most strongly with a single school, shown by its color. When a gem is used as a reagent of its affiliated school, it counts as twice its value. Clear diamonds and other colorless stones have no single affinity and always count as twice their value.

Color (School)	10 gp	50 gp	100 gp	500 gp	1,000 gp	5,000 gp
Red — Evocation	red agate	carnelian	garnet	red spinel	star ruby	ruby
Orange / Yellow — Transmutation	tiger eye	citrine	amber	topaz	fire opal	jacinth
Violet — Illusion	fluorite	amethyst	iolite	tanzanite	purple sapphire	alexandrite
Rose / Pink — Enchantment	rhodochrosite	rose quartz	coral	morganite	pink sapphire	pink diamond
Blue — Abjuration	lapis lazuli	turquoise	blue tourmaline	aquamarine	blue sapphire	blue diamond
Green — Conjuration	malachite	chrysoprase	jade	peridot	emerald	green diamond
Iridescent — Divination	labradorite	moonstone	rainbow moonstone	boulder opal	opal	black opal
Black — Necromancy	obsidian	onyx	jet	black pearl	black star sapphire	black sapphire
Colorless — Any (universal)	milky quartz	rock crystal	white topaz	white sapphire	diamond	flawless diamond

Gems weigh between 50 per pound and 5 per pound.

Hastening a Craft with Gems

When the rules for Crafting a Magic Item (including Spell Research) are used, one or more reagent gems may be used to hasten the work. Total the value of the gems used. Take that total as a percentage of the crafting cost; the crafting time is reduced by that percentage, to a maximum of 50%. The gems are consumed during the process.

Example. Rare item (2,000 gp, 5 weeks). A 1,000 gp gem halves the work to 2.5 weeks, as does a 500 gp emerald if the item is conjuration-based.

Buying and Selling Gems

A gem may usually be sold for its listed value, but buying a gem is more difficult. Small stones up to 50 gp may be found in a city's markets, but larger gems, and especially those of 5,000 gp or more, are bought rarely, at a premium, and never on demand. Buying more than a few gems may cause prices to double or more and is almost certain to cause rumors.