CACHES AND CASES
Philosopher's Caches & Alchemist's Cases are the building blocks of most of the alchemy system. You could think of a Philsopher's Cache as a place to get ingredients, and an Alchemist's Case as a place to get recipes.
They are both level 1 formulae, which can be made from components readily found in towns/games/ZOMG.
There are four routes for each of them, with the first 3 being the same except that they require either bugs or paper or flowers, and the 4th being made from 5 or 10 Gold Giftboxes respectively. A Case requires 4 times as much towns' material as a Cache.
Inside the Cache
When you successfully craft a Cache you have a few options. You can sell it as-is, or you can open it. If you open a Cache, you will get one of 10 different 'grab bags' named after different gemstones- Amethyst, Aquamarine, Diamond, Emerald, Garnet, Gold, Platinum, Ruby, Sapphire, or Topaz.
Each of these contain a different set of components which are used in some formulae.
You can look
here for a list of which components are available in which caches, and
here to find out your likelihood of getting a particular bag when opening your Cache.
When you have got your gemstone cache, you can select the component that you would like from it simply by clicking on the desired component, or alternatively you can sell the cache untouched.
Here I am about to get a Tasty Ham out of a Sapphire Cache.
My suggestion if you don't want the Cache that you get, is to sell it unopened. In general, the Caches are more desirable & valuable than any of the components within them. Most of the loose components otherwise found in caches on the Marketplace are remnants from the previous Cache system.
Inside the Case
If you open an Alchemist's Case, it will give you one formula. The formulae in here are all Alchemy exclusive, and not found in Enki's Catch, Enki's Drop, or in the Bifrost (the other main home of formulae). Obviously like a lot of other things on Gaia, there is an element of chance, with super desirable formulae (e.g. Erebus Moon, Nice Suit For Work, Backwings Quests) being more rare than others.