Adalbertus Aloysius Kalkstein is a master alchemist who lives in the non-human district of the Temple Quarter in Vizima. He is also honorary chairman of the Alchemists, Geomancers, and Pyromancers Club, and rival of the Oxenfurt Inventors' Club. He lives right next door to Golan Vivaldi, in fact, and just around the corner from Shani. Geralt first meets him in the Outskirts where the state of quarantine is making it difficult for anyone to enter the city, and the alchemist is no exception. While Kalkstein waits to have his pass accepted, he bides his time at the Inn.
As an alchemist, he also buys and sells items related to alchemy. Without a doubt, Kalkstein is an honest merchant. At the best prices, he will buy and/or sell:
He is very interested in anything alchemical or unnatural. On his first encounter with the witcher, he asks our hero if he can examine his body — for scientific purposes only! When Geralt takes exception, he then relents and asks if he can perform an autopsy upon his death. This does not really go over well either so they change the subject.
Later in Chapter I, Geralt meets Kalkstein a second time at the Merchants' Gate, where he is being threatened by Salamandra who are intent on taking his equipment, by force. After a quick round of swordplay, the bad guys are dispatched and a grateful alchemist offers Geralt a reward: his services any time the witcher is in Vizima, at a discount. It is also at this point in the story that Geralt realizes the full extent of the repercussions of the theft of the Witchers' Secrets from Kaer Morhen and his resolve to track them down and make them pay is renewed. In Chapter II, the witcher must seek out the alchemist again, but this time, it is the witcher who needs the alchemist.
Once Geralt gets out of prison and takes up his investigation of Salamandra, it does not take long before the name, "Kalkstein" crops up again. Remembering that the alchemist's place of business is in the Temple Quarter, our hero sets out to find it. The shingle outside Kalkstein's house says it all. It seems that the alchemist needs someone handy with a sword for his latest project. This seems to be the project that excites him most: opening the mysterious Mage's tower in the swamp. He had previously hired Berengar to look into it, but that witcher just disappeared.
It is entirely possible for the plot to take a turn where Kalkstein becomes the prime suspect in the witcher's investigation of Salamandra. During the autopsy portion of the investigation into the murder of the crown witness, the alchemist can be implicated. In that event, Azar (masquerading as Raymond) seizes the opportunity presented by Geralt's false conclusions and further blackens Kalkstein's reputation with tales of his alleged involvement with the criminal organization. Only after a confrontation with the real culprit at the Mage's tower does Geralt finally learn the truth.
In Chapter III, once the tower has been opened, it becomes Kalkstein's main base of operations for a while. And fortunately for the witcher, there seem to be no hard feelings if Geralt had implicated him in Chapter II. Their relationship merely continues as normal. Of course, if the alchemist was not implicated in Chapter II, there is nothing to forgive, so it is business as usual.
In Chapter V, we find the alchemist in Old Vizima, where tales of mutants and strigas roaming the streets have lured the curious scientist. If Geralt chooses the Witcher / neutral path, Kalkstein also becomes his armorer when it becomes necessary to fashion Raven's armor for the final battle.
- The absent-minded alchemist seems nice, but it is obvious that scientific theories are of greater concern to him than the more prosaic aspects of life.
- He lives in the part of the Temple Quarter inhabited by non-humans. He runs an alchemy workshop there, earning his living selling potions. But he devotes himself to his greatest passion — gnomish alchemy.
- The alchemist sometimes uses the services of witchers. Berengar used to work for him.
- Kalkstein has dealings with Vizima's criminal underworld. Strange company for an alchemist to keep.
- I have proved that Kalkstein is not the Salamandra leader. I'm glad, because I've actually grown fond of the alchemist.
- For the first time since I arrived at Kaer Morhen, I saw a truly happy man. The door to the tower in the swamp stood wide open, and at the thought of all the alchemical secrets waiting inside, Kalkstein was as delirious as a drunken dwarf.
- Even though he calls himself a scientist, Kalkstein is an alchemist, so he definitely dabbles in magic.
- Kalkstein is the author of many alchemical works, including a treatise analysing attempts to animate inanimate matter, an activity known otherwise as constructing a golem. Apparently the alchemist has been interested in this matter for years. Kalkstein's convoluted style makes his work difficult to read.
- Riots and fires in the city drove Kalkstein from his laboratory. I met the alchemist in Old Vizima, to where he fled.
Kalkstein is one of the most prominent characters in the game and is central to many quests:
- A Magic Formula
- A Mysterious Tower
- Anatomy of a Crime
- Armor, if Geralt chooses the Witcher / neutral path.
- Beauty and the Beast
- Berengar's Secret, indirectly
- Suspect: Kalkstein
- The Alghoul Contract
- The Crown Witness
- The Garkain Contract
- The Ghoul Contract
- The Sentry
- The Wraith Contract
- Vizima Confidential, as part of the investigation.
- What Lies Beneath
- According to one of the books he authored, Transmutations and Metamorphoses, his full name is Adalbertus Aloysius Kalkstein.
- Kalkstein is one of the few merchants who will purchase Wolf pelts and Barghest skulls from you. He buys all the expensive minerals, a good way to get some easy cash. He also buys alp fangs (if you have an excess of them).
- In Chapter III, Kalkstein tells Geralt about his new ground-breaking theory of invisible particles constituting matter, in constant movement and interacting between each other. This is a witty nod to what we now know as atoms.
- According to Geralt's quest comments in his journal, Kalkstein seems to be of gnomish heritage, and Geralt really wants to ask about it, but Kalkstein would be rather tall for a gnome.
- It is possible that Kalkstein's enthusiasm for doing an autopsy on the witcher is a nod to the mage, Gorazd in the novels who offers Geralt gold for the opportunity to examine witcher eyes — when he is ready. Or perhaps to a medic, who wanted to examine Coën after he died in the Battle of Brenna.
- "Kalkstein" is both the German and Norwegian word for "Limestone".
In a conversation with the tailor Elihal, the elf informs Geralt that Kalkstein was captured and burned on a stake by witch hunters in Novigrad's Hierarch Square not long before witcher's arrival. And as the alchemist perished fiery beasts circled his pyre, then rose into the sky and exploded to form letters "Radovid sucks flaccid cock".