DENVER — Doug Nichols was a world-class rock collector, from the time he was a child until his death at 67. He was a palynologist, an expert in the study of fossilized pollen and spores.

Nichols died Jan. 21 following leg surgery.

Nichols collected rocks that were hundreds of thousands of years old, soaked them in a special solution and then determined from what age in history they came from, said Kirk Johnson, curator at the Denver Museum of Nature and Science.

“It’s almost like magic,” said Johnson, who worked with Nichols for more than two decades. “We can tell from tiny pieces of rocks, and the imprint of pollen or spores on them, what a forest looked like a million years ago,” said Johnson.