Thomas Jones was still a teenager when his mutant powers first manifested. With little control over his powers, Thomas could turn objects he touched into gold. This drew the attention of the Troll Associates, a group of trolls. Centuries ago, trolls had been driven underground by humanity, but the Troll Associates wanted to reclaim the British Isles for their kind. The Troll Associates kidnapped Thomas and told him to create an abundance of gold to collapse the British economy, but Thomas refused to comply.

Meanwhile Thomas' mother had witnessed her son's abduction by the trolls and thought that the trolls were mutants. She called X-Factor for help (at the time, they were still posing as human bounty hunters who targetted mutants). X-Factor tracked down the trolls, following a trail of gold that Thomas had left behind, but the trolls defeated and imprisoned X-Factor. The trolls then tried to force Thomas to obey by threatening his mother.

To protect his mother, Thomas turned the leaders of the Troll Associates, Phy and Phee, into gold. The Troll Associates retreated and Thomas then turned the golden trolls into lead . X-Factor placed the leaden trolls in Hyde Park as statues. Thomas decided to study biochemistry so that he could restore the leaden trolls back to normal.

A few years later, the Troll Associates kidnapped Alchemy's mother. Alchemy was forced to obey them, but he secretly called X-Factor for help but his call was forwarded to the X-Men. On their way to restore the leaden trolls back to normal, the Troll Associates and Alchemy ran into Excalibur. The two groups fought and Alchemy turned Captain Britain and Meggan into gold. The X-Men met up with Excalibur and together they tracked down the trolls, but both groups were captured. Excalibur-leader Nightcrawler managed to convince the majority of the trolls that the Troll Associates' methods were wrong.

He challenged the new leader of the Troll Associates, Phough, to single combat, while Excalibur and the X-Men freed themselves. Phough then tried to kill Alchemy's mother, but Nightcrawler saved her and Alchemy turned Phough into a golden statue. Alchemy then revealed to Excalibur and the X-Men that, due to his biochemistry studies, he could now restore humans back to normal and restored Captain Britain and Meggan.

Alchemy is one of a handful of mutants to retain their powers after the events of the House of M