For ten days, SH and I explored Yellowstone National Park. We visited just about every geothermal feature: geysers, fumaroles, hot springs, mudpots, and hot spring terraces.

The one feature SH really wanted to see was the Grand Prismatic Spring — 370 feet in diameter and more than 120 feet deep and scalding hot. The incredible colors of turquoise blue, green, yellow and orange are due to thermophiles, bacteria which feed on the hot minerals of the spring. Except in the turquoise blue center which is too hot for any living organisms. We walked to the overlook above the spring as the last stop of our tour of Yellowstone. Our guide said he had never come to the spring in the morning since most folks want to see it before the crowds; however, we got there in the later afternoon when folks were tired and leaving after a long day of sightseeing. Our guide observed he had never had such a good view of the spring because in the morning the steam rising off the hot spring in the cold air obscures the colors.

The Grand Prismatic Spring was like a bright agate dropped from the sky with bands of vivid color around that piercing turquoise.

We saw many of these bright turquoise pools and they reminded me of huge pieces of sleeping beauty turquoise with no cracks or discolorations. Just dropped from the sky as though they were eternal tears of God.

Another thing we noticed about each of the geothermal features was the sounds which they made. Each geyser or mudpot or hot spring had its own distinctive sound. It was like the entire caldera of Yellowstone was a giant stove with many different pots boiling and bubbling and gurgling. Some of the springs glubbed as if they were big pots of cooking oatmeal. Some sprightly spritzed like a tall cylinders of spouting hot water which occasionally splashed out. Some sounded like a percolating coffee makers.

Often we would just stand still and listen to the voices of the geyser and hot springs — catching their music between gusts of wind or bits of conversation.