The classic alchemy was a combination of occult and scientific (for the time) understandings in the effort to transform base metals, like lead, into gold. So, in a nutshell, it was a middle-ages Mashup of mysticism and 'get-rich-quick' schemes.
In the end it gradually resulted in the realization that elemental materials are defined as such because they are pure and unified in their form and so unable to be changed. But in the process other elements, their interactions, and eventually their make-up was discovered. Birthing things like a fledgling version of the periodic table, chemistry, and in the end molecular science as we know it today.
As alchemy faded into history, that mysticism and occult side of it was lost for a time. Dropped from the attitudes of science. But more recently, in the latter-half of the 20th century, that aspect saw a resurgence of sorts. Not as a science but as an allegory and metaphor to represent purification of the proverbial leaden soul and transmuting into the purity of golden enlightenment. All of the old symbols and explorations returned, but as occultism and mystical metaphor to spiritual concepts and ideals.
Alchemy in effect grew from the physical pseudo-sciences (in development/larval form of) into an ideology of spiritual development.
So, to answer your questions; I do think it is worth studying, even if it is a surface-level understanding knowing the history and evolutions it followed can be a surprising source of spiritual allegory. At the very least it represents much food for thought.
But then again I am a bit biased as I firmly believe a person should learn anything they can from wherever they may find it. Wisdom hides everywhere. And the more you examine differing paths the faster you see how they all wind up the same mountain. However you reach the summit, we are all entreated to the same view.
Does it actually involve elements, portions and resins? ...Once it did, but it has since evolved into the realm of metaphor. If you want to learn chemicals and elements draw from science and chemistry. Or in chemical healing medicine and herbology/natural medicine. It is a more ... up to date source.
Perhaps look at Alchemy... at least modern alchemy... as the effort to marry together the physical and the spiritual. The scientific with the mystical. Examination with wonder. In my book all are things for anyone to strive for regardless of how they go about it.
