Alchemy is generally dated back to being practiced in Old Kingdom Egypt; a period from the Third Dynasty through to the Sixth Dynasty (2686 BC-2181 BC).
In some alchemical and religious texts around the world the creation of the Heavens and the Earth are attributed to alchemy.
Carvings on rock have been discovered that relate to alchemy in Northern America dating back to pre 4000BC.
The main goal of alchemists was to produce the philosopher's stone and the elixir of life, the quintessential food for the spirit. Through the European Middle Ages (410 AD to 1453) there were many alchemists who’s focus was to transmute basic metals into gold. A decline in popularity of alchemy after this time is due to the rise in popularity of atomic structure theory and chemistry.
A brief history of atomic history can be found at: http://www.neoam.cc.ok.us/~rjones/Pages/…
Assaying (chemical identification techniques) used today are not finely tuned to identify the subtle existence of alchemical substances. Assaying techniques typically burn substances and match the color of the flame against a chart of previously recorded data on known substances and elements, elements as seen in the periodic table. Alchemical substances are in a changed state, and are invisible using these methods. However they remain visible to the naked eye and are often mistaken for chemicals that they are not.
Today there are many practicing alchemists. There are also new scientific ways of obtaining alchemical substances. However, for the most part alchemical substances have evaded chemical analysis for hundreds of years due to the above mentioned non-inclusive cut, burn, dry methods used by the modern science industry.
Modern chemistry explains very clearly the components of matter as atoms but does not account for consciousness or spirit. In this way it does tend to ‘disprove’ alchemy as a science. The gibberish language that alchemical texts are coded in does not help alchemy’s popularity and integrity either.
Previously alchemy was covered in secrecy, coated in codes and dunked in myth, presumably to guard the secrets of obtaining eternal life, to protect the price of gold, and for fear of persecution during times when non-Christians were being put to death (in spite of the many alchemical mentions in the Bible).
In the past two decades the practice of alchemy has had resurgence all over the world after a farmer called David Hudson found a mysterious substance at his hobby mine processing plant. In a long series of adventures and many millions of dollars later David Hudson shared his findings in seminars throughout North America.
For some practical advice you may find the following books helpful:
The Elixir of Immortality: A Modern-Day Alchemists Discovery of the Philosophers Stone by Robert E. Cox
Ormus Modern Day Alchemy: Primer of Ormus Collection Processes Reference Edition by Chris Emmons
Real Alchemy: A Primer of Practical Alchemy by Robert Allen Bartlett
Also visit: http://www.levity.com/alchemy/
I have no affiliation with the websites or books mentioned above.