What This Replaces
These rules are meant to complement the rules found in the PHB. Specifically, there are adjustments to the types of ritual components and to the rituals themselves.
There are three types of ritual components: Specific, Focus, and General. Both are required to be met and are sometimes expressed in gold point equivalence. These are for convenient measurement of their value, and does not vary with market prices. If a shortage of rare herbs doubles the cost of rare herb components, you may not use half as many herbs for the same total cost. Instead, you would have to pay the extra market cost or find a substitute.
Specific costs are typically rare items whose destruction or sacrifice is necessary to the completion of the ritual. Only edited or custom rituals have Specific costs. If a ritual is cast without the necessary specific costs, the ritual has no effect and no components are expended. Sometimes there will be substitutes offered for the specific costs. A ritual may require 100ml of Rendiol blood or a Rendiol's scale. You may choose to expend one of these or the other, but not both.
Focuses are magical catalysts whose presence is required for the completion of a ritual. If a ritual is cast without the necessary focus, the ritual has no effect and no components are expended. Sometimes there will be substitutes offered for the focus. A ritual might require a polished mirror or a 100gp diamond. You may use one focus or the other, but not both. Focuses are not destroyed when a ritual is cast, so they can be re-used multiple times. Gold values on focuses are proxies for size, not transaction value.
General costs are common components with inherent properties that allow them to be converted into magical power. Some forms of general components are more effective than others, and using a substitute form of component requires 25% additional components. You may use any proportion of general components so long as they sum up to the total general cost of the ritual. If a ritual is cast without the necessary general components, the ritual has no effect and no components are expended. A ritual might require 500gp of rare ink, and you can pay for the ritual using 300 gp of rare ink and 250gp of a substitute, such as alchemic dust. Mana Crystals never suffer this penalty.
See Ritual List