My wife and I were looking for something to do one Saturday afternoon, and we had heard there was a calcite onyx quarry near Nephi. So we hopped in the car and drove down the I-15 to Nephi, took the Nebo Loop exit and drove into the mountains. There had been a number of bad fires earlier that summer, and the hills were covered with blackened shrubs and dead trees. Enough time had passed for the vegetation to grow back. A light rain was coming and going, and the scenery was so green that I almost thought it was spring.
The loop turns north a few miles into the canyon, and then forks. We stopped the car in a little parking lot and started hiking up the hill between the two roads. Luckily, the rain had stopped, but there had been enough to turn the ground into sticky clay. Every ten steps the clay would build up six inches thick on the bottoms of our shoes and we’d send it flying off with a good kick. We came to a cut in the hillside and could see the striped layers of calcite. The collecting area was fairly small, and the onyx was limited to a few veins, but it was nice looking stuff. Mostly white, red and brown stripes. We both filled our coat pockets with it and headed back to the car just as the rain started falling again.
When we got home I looked on Google Earth and realized that we were so excited to find a collecting site that we never looked for the main quarry. If we had walked on another 50 feet we would have found plenty of material. We came home with enough, though, and calcite is easy to cut and polish.