Before the Plaza fountain we know today was constructed in 1910, the Plaza had a “Mineral Fountain,” (pictured above.) Along its outside boundary were a number of what the Weekly Arizona Journal-Miner described as “peculiar red rock[s]…about which there has been much speculation as to what [they are].”
“The rock is peculiar in that it is susceptible of a good polish and it contains practically no grit," the paper continued, and is very soft, as it can be whittled with a knife like a piece of chalk. When the fountain was being built this rock attracted general attention from all who saw it, but no one seemed able to classify it.”
Then in April, 1903, two investigators identified the source of these peculiar rocks, not too far from Prescott. They gathered samples to take to several different assayers and what they found was a great surprise to everyone.