I have been intrigued by this mountain since moving to Colorado in 1971. Mt. Antero is the 10th highest peak in the state at 14,269 feet in elevation. It is located between the towns of Buena Vista and Salida and borders the west of the Arkansas River valley in the Collegiate Peaks range (see map). It was first prospected in the late 1800's, as were most of the rest of the mountains in the state. White men were first searching for riches in elusive gold and silver outcrops, but it wasn't gold or silver that was the real treasure here. Rather, it was aquamarine crystals, those beautiful sky blue to sea green colored variety of gem beryl. To make it more intriguing, all known gem deposits here occur above timberline, making it the highest known gem locality in the United States. The aquamarine occurs in pockets or bubbles in the granite rock, mostly in what is known to scientists as miarolitic cavities. It is frequently weathered out into the scree and talus. Associated minerals can include well-crystallized specimens of smoky quartz, colorless quartz, white feldspar (mostly microcline, but also adularia and clevelandite); green, violet, or colorless fluorite (in octahedrons); apatite and fine colorless to sherry phenacites. More rarely, one can find colorless to sherry to orange crystals of topaz and the rare beryllium mineral bertrandite.

Collecting in the early years was all by foot, requiring a difficult climb from the base. In the early 1950's a company from Texas built a road up the west side of the peak to mine beryl and possibly molybdenite. The venture was short-lived, as it soon became apparent that the beryl was not concentrated enough to make mining economical, especially considering that the mining season at that altitude usually lasts only from June through August. The best thing about it was eventually providing access up the mountain for the more average rockhound. One of the problems of high-altitude collecting is the constant threat of storms and lightning most afternoons, definitely a scary thought above timberline. Another is altitude sickness and possible hypothermia for those unprepared for sudden changes in temperature. I must stress that working at high altitudes is definitely not easy. Having a vehicle nearby for quick retreat is definitely comforting, although there are always a number of hikers up there every summer who prefer the challenge of doing it the harder way (or perhaps have no other choice). It is always a challenge and adventure to go up the mountain however, whether by foot or four-wheel drive. The 7 mile "one way" drive is rocky, bumpy, steep, narrow, and above timberline involves some hazards. One miscue on the switchbacks or shelf road could result in a tumble of a thousand feet or more! If you make the trip by vehicle, please stay on the established trails and do not cut across the fragile tundra areas. There are both patented and unpatented mining claims in the area, but most of the land is considered open for hand-digging. The only one I know of that is off-limits is the actual tunnel of the California Mine (patented claim). As of a few years ago the access portal has been caved in and covered with slide debris. Things can change, so be aware of any strictly enforced "keep out" areas that may exist.

Collected in 1995 by geologist William Hutchinson.

The road is in some ways a disadvantage to serious collecting as well as a distinct advantage. With more people comes more collecting. With more collecting comes more depletion. The problem is that the "easy stuff" has mostly disappeared now. If you aren't with someone who knows the area, you can easily miss a likely digging area as most of the surface float has been picked up already. Digging has always been hit and miss (mostly miss) and good finds scarce. The collector who finds a large pocket of fine aquamarine is indeed extremely fortunate. If we only had x-ray vision to see under the surface! But there are many good areas where a reasonable amount of scratching and shoveling should result in a few decent small smokies or beryl matrixes, maybe even some fluorite or one of the other desirables or a chip or two of aquamarine. Success often depends on knowing a bit about the geology, as well as experience. Perseverance pays!

The color of the aquamarine here ranges from colorless (actually "goshenite") to deep blue, with lighter blues being the average. Green colored stones are rare as are yellows (heliodor) which will always have a green tinge. I was lucky enough to discover and identify the first morganite beryls from here (morganite is peach to pink beryl) in a prospect pit on Carbonate Ridge near the famous California Mine (located a few miles to the southwest of the main peak of Mt. Antero). Clear areas large enough to cut over a couple of carats clean are uncommon. Most crystals have veils or inclusions or etching which prevent maximum yield. The largest stone I have cut from here that was eye-clean is about 9 carats. I have seen several specimens that would yield stones up to 15 or 20 carats or more, some of which are very fine deep blue. If you find a perfect terminated crystal however, it is usually considered a sacrilege to cut it into gemstones. They are beautiful in their own right and much scarcer than broken chunks or pieces or damaged crystals which can be cut. To cut up or disassemble a fine crystal group (crystals of different species attached to matrix or with other crystals implanted thereon) should be made a criminal offense! (And keep in mind this is a cutter talking). I have seen gorgeous specimens from here with phenacites or fluorites implanted on the termination or side faces of the aquamarine crystals.

If you are interested in learning more about this fascinating place, may I suggest the book Antero Aquamarines by geologist Mark Jacobson, and published by L.R. Ream Publishing. It is a limited edition printing, but the soft cover version can be had for around $15-$20.