The Red Phoenix
Your society of alchemists has long been a secretive group, wary of outsiders and protective of your knowledge. You have sacrificed much to attain what you have, but it seemed like you would never reach your ultimate goal: the creation of gold.
That is, until one of your order purchased an ancient text from a street vendor. It was filled with notes that point to a reaction called 'The Red Phoenix.' In it, the author details the methods by which he commonly performs experiments, some of which are simple, some expensive, and some even required his own blood. While the book is clearly a masterpiece, the blood stains on the back pages do give you some pause. How did this book end up in the hands of that merchant anyway?
Unfortunately, it seems whoever stole the book ripped out the page with the formulas. But fortunately, the author's methods have set your group on the right path. As you begin to taste success, you and your companions set to work with a zeal unlike anything you would have thought possible.
All that remains is the question of who will be the first to discover the secret.
Some Historical Context
Symbolism in Alchemy
To modern scholars, the study of the practices in alchemy has been difficult, because alchemists themselves were very secretive. Alchemists truly believed they were on the path to discovering things like the secret to eternal life and the ability to produce gold at will, a dangerous knowledge considering all medieval economies were based on the value of gold. In fact, many rulers simply made the study of alchemy illegal.
In order to protect their knowledge, alchemists kept their notes in code and often wrote under false names. They used symbols for the ingredients they worked with as well, referring to various chemicals as animals like the 'white eagle' and the 'red dragon,' and they may even draw an image of a red dragon eating a white eagle to represent the reaction between the two chemicals.
Learn more: Lawrence Principe on Alchemy (youtube.com).
The Color Red
The final stage of the alchemical process was symbolized by the color red, known to alchemists as "rubedo," or Latin for redness. It was associated with the successful creation of gold.
Alchemists were concerned with far more than transmutation of elements though. Over time, alchemists studied mysticism and hermeticism a great deal too, and assigned various symbols to these studies. In particular, birds were thought to represent various states of the the spiritual process. The phoenix was thought to represent the final stage of development of the soul; the freeing of the spirit from the bounds of the physical.
Learn more: The Birds in Alchemy by Adam McLean (levity.com).