R&G REVISITED: IDAHO STAR GARNETS
Just Drive Down Emerald Creek to Pee Wee Gulch (February 1985)
Brilliant colors enhance the beauty and add to the value of many of our gemstones, especially those that are clear or translucent. And I like any color… as long as it is red. For that reason, the blood-red ruby is about my favorite gemstone. And in museums around this country and in Europe I have seen carefully cut cabochons containing startling six-rayed stars that seem to slide over the surface of the stone as it is rotated in the light. It is no wonder that, for hundreds of years, the star ruby has been one of the favorite stones of royalty.
Unfortunately, I couldn’t buy a star ruby, even if I mortgaged my mother-in-law’s false teeth. Then, a couple of years ago Phil Andrist, a dealer at a rock show, from Bandon, Oregon showed me some beautiful, translucent, burgundy red, almandine garnet cabochons that contained some very nice four- and six-rayed stars.
The material had come from the Emerald Creek area in northern Idaho, and he said he had collected it himself. He had both finished cabochons and rough material and, since I like do things myself, I bought some of the rough. Then, following Phil’s directions, I made a couple of cabochons and was really pleased with the results.
As far as we know, star garnets are found only in northern Idaho and in India. The effect is called “asterism,” meaning star-like. Six-rayed stars are found in garnet, ruby, sapphire, and certain quartz stones, but only garnet has both four- and six-rayed stars. The phenomenon results from light reflected from rutile needles, or crystals, aligned in a certain pattern. Garnet stars can best be seen when the stone is cut as a cabochon and viewed in the sunlight, under a bare bulb, or in the beam of a sharply focused flashlight.
Andrist’s dark red, translucent stones, crossed with two or three shimmering, light colored lines, were enough to start my heart pounding. And when I made a couple of cabochons from the weathered brown material I purchased, and examined them in the sunlight, I was ready to head for the hills. So when Spring came, and we were sure we wouldn’t be snowed-in on a wind-swept ridgetop, my wife and I, and Lou Braun, outdoor photographer and his wife Ethelyn headed north.
It was mid-afternoon when we pulled into the Emerald Creek Campground operated by the U.S. Forest Service. We stopped just long enough to eat a sandwich, then my wife and I headed up the road to the Forest Service diggings on Pee Wee Gulch. About a mile from the campground we saw a hand-painted sign that said, “Shorty’s Diggin’s,” and across the creek we could see several big piles of gravel with about a dozen people clustered around them. We made a mental note of the location and promised ourselves that we would check the place out before we returned home.
It was 4:30, a half-hour before closing, when we pulled into the Forest Service parking area. So, I ran up the trail to where several people in boots and rain gear were digging in muddy holes in the bottom of the draw. One woman had a plastic bag containing two or three pounds of nice garnet crystals that varied from marble size, down to some that were no bigger than a pea. She said that four of them working in the same hole had dug them out that day.
Garnets in the Emerald Creek area had their beginning between 100 and 170 million years ago through a process called metamorphism. This is another word for “change in form.” In this instance, changes occurred when shales, clays, and mudstones were subjected to intense heat and pressure, and the iron, silicon, magnesium, aluminum, and oxygen contained in these materials converted into garnet crystals.
It has been estimated that the heat was between 380 and 580 degrees Centigrade, and the pressure between 5,000 and 5,500 bars. A bar equals 14.66 pounds per square inch. The higher the temperature and the greater the pressure, the larger the garnet crystals.
For some reason, during the development of some garnet
crystals, a line of tiny, hair-like, parallel crystals of rutile, developed inside the gemstone and were orientated along the axial boundaries of the “mother” crystal. Hexagonal gemstones, which also include the ruby and sapphire, have three opposing axes and the rutile crystals grow in three directions, producing a six-rayed star.
Four-rayed stars develop in garnet when the gemstone is formed in a cubic or isometric system. In this case, there are two axes at right angles to each other and, when the stone is properly cut and viewed under the correct light, a four-rayed star can be easily seen.
Under properly controlled conditions, perfect six-rayed stars with 60-degree angles between the arms, or four-ray stars with their arms forming 90-degree angles are produced. But Mother Nature’s laboratory is far from perfect. During the formation of the garnet crystals, the heat and temperature may have varied widely, and the supply of minerals may have been interrupted. As a result, some garnets contain no stars. In others, the angle between the arms may vary, and some rays may be shorter than the others, or they may be entirely absent.
It was a few minutes before 8 the next morning when my wife and I, and Etheyln drove over the narrow bridge across Emerald Creek and stopped beside the gravel piles. A half hour later, more than 20 people were searching for garnets, and the gravel piles looked like giant ant hills. Most of those present had been there before and seemed that everyone had their favorite way to look for garnets.
Some climbed the steep sides and scratched in the gravel. Others worked at the base of the piles and examined the material as it rolled down the slope. Some carried water from an excavation pit and poured it over the side of the pile. They claimed it made the garnets shine so they were easier to see. Others said the water made the gravel shine and it was more difficult to see the garnets. One group shoveled the gravel onto a canvas, spread it out, and examined it carefully. Strangely enough, it seemed that all were about equally successful. Everyone that is, except my wife and I. We worked side by side with Ethelyn, and she found more and better material than both of us put together.
Regardless, everyone seemed to be glad to be out in the sunshine. There was an exchange of good-natured banter, nd every now and then we heard a squeal or shout of delight when someone found a particularly good piece of material.