why does the author take time to describe the crysrals precisely?

Monet's illness was thought to have started in the caves, the illness got into his bloodstream. Could the crystals have been a cause?

"The logs were surrounded by crystals, white needles of minerals that had

grown out of the rock. The crystals were as sharp as hypodermic syringes, and they glittered in the beams of the flashlights."