Photo of flawless iolites (>1 carat) and the Gemhunter with foot on boulder containing pink sapphire and millions of carats of gem kyanite!
Of the discoveries I made, these were probably the most exciting. I may have found two world-class multi-gem deposits containing iolite, I also found the largest iolites in the world.
Giant iolite gemstones & potentially the largest colored gemstone deposit in the world were discovered in the Laramie Range of Wyoming. Gemstones weighing >24,000 carats were recovered from Grizzly Creek with large masses that remain in outcrop estimated to include stones >1 million carats. Another deposit found nearby in the Sherman Hills may have an estimated >2.4 trillion carats of gemstone based on past drilling, trenching and mapping.
A group of faceted iolites and rubies from the 1996 Palmer Canyon multi-colored gemstone discovery.
The Palmer Canyon discovery was followed by discoveries at Grizzly Creek, Sherman and Ragged Top Mountain, and Owen Creek. These gemstones were discovered and some were even predicted to exist by having an understanding of geology (Hausel and Sutherland, 2000). And one can still bet other iolite and ruby deposits will be found in this region based on geology.
These discoveries represent the largest iolite deposits and individual iolite gemstones found anywhere on earth. Yet, believe it or not, they remained undiscovered until 1996, 2004 & 2005.
One of the more exciting gemstone discoveries made was gem-quality iolite in Palmer Canyon, Grizzly Creek and at Round Top Mountain. The Palmer Canyon discovery was made west of Wheatland. This led to gem discoveries that include a world-class deposit at Grizzly Creek and a second probable world-class deposit at Ragged Top Mountain. This latter deposit could lead to classification as one of the largest gemstone deposits ever found; however considerable field and laboratory investigations are necessary (Hausel, 2005b). I was able to verify the presence of flawless gem iolite, but because of the property being on private land and a lack of support by the Wyoming Geological Survey, I was unable to complete studies on this project.
Gemologists refer to gem cordierite as iolite or water sapphire. Geologists & mineralogists refer to it as cordierite. The mineral has also been labeled as dichroite. Cordierite typically is found in the vicinity of other alumino-silicates such as andalusite, kyanite & sillimanite. Host rocks include alumina-rich mica schists (metapelites) that have been subjected to amphibolite-facies metamorphism. Cordierite is also found as a replacement mineral in alumina-rich syenite-anorthosite complexes & in some shales.
Flawless 0.5 carat Palmer Canyon iolite.
Iolite may form short prismatic crystals with rectangular cross sections as well as granular masses and nodules of various shades of blue, bluish-violet, gray and/or brown. Fresh cordierite has a hardness of 7 & specific gravity of 2.55 to 2.75. The hardness is favorable for durable gemstones. The principal deposits that supply much of the world’s market are Sri Lankan placers in spite of low specific gravity of the mineral (i.e., it is not favorable to concentrated in placers).
Iolite exhibits strong pleochroism that varies from light gray, dark violet-blue, to light sapphire blue. The gem may appear deepest blue when viewed down the c-axis and light blue to light grey in other orientations. These color variations are one of the attractive features of this gem. Iolite is often enclosed by a reaction rim of pinite (Hausel, 2002).
Group of 8 to 12 carat Wyoming iolites (photo courtesy of Vic Norris).
The luster of iolite is vitreous & when polished, it becomes increasingly lustrous. Gems >12 carats are unheard of, even so, rough material collected by me at Palmer Canyon & Grizzly Creek represent the largest iolite gemstones in the world: many are much larger than 12 carats - for instance I found several that were >100 carats with others >1000 carats. In Wyoming, cordierite has been found in gneiss with quartz and biotite as porphyroblasts with xenoblastic texture (Hausel, personal field notes, 1995).
Iolite is reported in Canada, India, Myanmar, Sri Lanka, India, Brazil, Tanzania, Finland, Germany, Norway and the United States. The highest quality gems are found as pebbles in Sri Lanka and as porphyroblasts (large crystals) in gneiss in Wyoming.
Palmer Canyon Blue Star - 1,715 carats.
Large nodular masses of iolite were discovered in two separate deposits in Archean (>2.5 billion year old) gneiss in Wyoming & a giant disseminated deposit may occur in the Laramie Range anorthosite-syenite batholith (Hausel 2002; 2004; 2006a). These deposits represent the largest in the world, but remain poorly explored (Hausel, 2005b).
Two deposits (Palmer Canyon and Grizzly Creek) are poly-gem occurrences with ruby & sapphire as accessory minerals along with considerable kyanite in schist, glimerite (vermiculite) & gneiss. The metapelites represent enclaves of aluminous schist & gneiss. A third deposit in the vicinity of Ragged Top and Sherman Mountain is hosted by anorthositic-syenitic rocks (1.5 Ga).
Another of many flawless iolite gemstones from Palmer Canyon.
This latter deposit remains unexplored even though granular gem-quality iolite was verified by myself (Hausel, 2006a). Local enrichment of iolite at Palmer Canyon and Grizzly Creek is promising. It is not uncommon to find gems of several hundred carats in both deposits with occasional masses weighing thousands of carats!
Iolite was discovered in 1995 at Palmer Canyon during field reconnaissance by Hausel (2002). The deposit lies along the eastern flank of the central Laramie Range 16 miles west of Wheatland within Archean quartzofeldspathic gneiss, granite gneiss, pelitic schist, and biotite-chlorite-vermiculite schist north of the Elmer’s Rock greenstone belt. To visit this area, fly to 'Palmer Canyon Rd, Wheatland WY 82201' on Google Earth which will place you about 4 miles west of the deposit. A shallow prospect pit was dug in vermiculite prior to 1944. Only a very small amount of vermiculite was found. The vermiculite contains chlorite, kyanite and corundum. Samples of vermiculite-chlorite-biotite-corundum schist collected from a small prospect pit contained as much as 10-20% corundum. A minor amount of corundum is gem quality. Several specimens produced high-quality ruby and pink sapphire.
Beautiful faceted 12-carat iolite from Grizzly Creek.
Cordierite was discovered in nearby quartzofeldspathic gneiss. Samples of cordierite gneiss yielded transparent cordierite grains including several weighing >100 carats. Some gneiss collected from the property contained as much as 20% transparent cordierite. The cordierite occurs as rounded to disseminated grains and large nodules. Foliation in the host rock parallels the margin of nodules and in some samples appears to terminate against the nodule boundary, suggesting that some of the cordierite formed during a post regional metamorphic event. Nearby, kyanite schist contains 20 to 50% excellent, light to sky blue with lesser tawny, green & red gem-quality kyanite prisms.
Transparent blue iolite occurs as large porphyroblasts, nodules & disseminated grains in gneiss adjacent to corundum and kyanite schist. The iolite was traced over a strike length of 500 ft and continues under soil for an unknown distance. A handful of large nodules were found at the time of discovery that include a raw, high-quality transparent gem known as the ‘Palmer Canyon Blue Star’ of 342.8 grams (1,714 carats), which was the largest iolite gemstone in the world at time of discovery. In addition to clear, transparent, violet blue gem-quality cordierite, some black translucent cordierite (‘Palmer Canyon Black’) was recovered. The Palmer Canyon Black produces attractive cabochons.
Much of the high quality rough material ranges from pleasing violet to a very light-blue color with only a hint of cleavage and parting. Microscopic examination shows few mineral inclusions in some gems. Gray to dark gray cordierite has well-developed parting and cleavage. A group of cabochons weighed 0.27 to 3.02 carats. These are dark-gray to black, translucent to opaque, near gems with distinct cleavage, parting and some fractures.
Two poor quality specimens were faceted that yielded a 3.9-carat lozenge-cut stone and a 3.4-carat marquise. Both were flawed with visible cleavage and parting. However, both produced surprisingly attractive jewelry when mounted in necklaces. Some bluish gray to gray translucent to cloudy material represents rehealed mylonitic cordierite that is poor-quality
This is one of the greatest gem discoveries of the century in the US. Grizzly Creek is accessed from the Palmer Canyon road about 4 miles east of the Palmer Canyon deposit at the base of the Laramie Range. To fly to this deposit, fly to 'Grizzly Creek, Rock River, WY' on Google Earth.
Following discovery of Palmer Canyon, similar deposits were predicted to exist in Grizzly Creek (Hausel and Sutherland, 2000). The thermal metamorphic event responsible for the large cordierite porphyroblasts at Palmer Canyon appears to have been widespread in the central portion of the Laramie Range. The earlier prograde metamorphic event produced large prophyroblasts of kyanite in the adjacent rocks.
It became clear during the initial field investigation that a major gem deposit had been discovered. Very large masses of gem-quality iolite were found, as well as large quantities of gem-grade kyanite. Cordierite at Grizzly Creek is surrounded by kyanite and sillimanite schists that contain minor corundum. The kyanite and sillimanite schist lies in a 300 by 5000 foot belt of metapelite. Much kyanite appears to be cabochon grade and has a very pleasing, sky-blue color, with some tawny and pink specimens.
Field assistant sits at Grizzly Creek outcrop. Nearly all of the rock behind him is iolite - potentially one, giant iolite gemstone!
The iolite is massive & forms large replacements of the schist. This one deposit may represent the largest iolite occurrence in the world. During reconnaissance, specimens of massive iolite were collected including one football-size transparent gemstone that weighed 24,150 carats – the largest iolite gem found in the world. It now resides in the Wyoming Geological Survey museum. However, this stone is dwarfed by masses of material that remain in place in Grizzly Creek. Some of the massive gem material will require quarrying operations to recover. It is very likely that gem specimens >1 ton (>4.5 million carats) could be recovered! In outcrop, the iolite is weakly iron stained on the surface & shows excellent light blue color & transparency on fresh surfaces. It is not known how much if any of this material has been destroyed by mylonitization (deformation). For example, several specimens collected at Palmer Canyon showed distinct mylonitic to ultramylonitic texture in thin section that resulted in a cloudy, light-blue and glassy material of poor quality.
Grizzly Creek Blue Giant (left) weighing in at 24,150 carats (largest recovered iolite gemstone in the world) & fresh broken surface at Grizzly Creek showing gem iolite. The Blue Giant was donated after I found it and displayed on the first floor of the Wyoming Geological Survey building at publication sales.
The first report of iolite in Wyoming was by Sinkankas (1959). A brief description indicated that iolite was a widespread constituent of schist & gneiss. In describing a deposit Sinkankas wrote, “…one estimate has placed the quantity available at thousands of tons (remember that a ton contains 4.5 million carats!!!). A couple of specimens I found along the southern edge of the Ragged Top cordierite deposit were glassy broken fragments of rather light blue color, verging towards grayish, small sections are clear and suitable for faceted gems.
Sinkankas also wrote ... "It is entirely possible that important amounts of gem quality material will be produced from this locality in the future.” Unfortunately, Sinkankas did not give a location: the whereabouts of this giant deposit remains unknown?
At the time of writing (1959), only one cordierite deposit had been described in the literature. The deposit, known as the Sherman Mountains deposit 15 miles south of Palmer Canyon. The deposit is in Proterozoic (1.4 Ga) metanorite, syenite and syenite-diorite gneiss of the Laramie anorthosite complex intrude the Cheyenne suture (1.8-1.6 Ga) zone. Widespread lenticular to tabular layers of cordierite is found in metanorite (hypersthene gneiss), gneiss and syenite along the southern margin of the anorthosite complex (1.5 Ga).
The host rock is described to have 50-80% cordierite. The occurrence lies 0.5-mile west of Ragged Top Mountain in a belt 0.3 to 1.2 miles (0.5-1.9 km) wide & 6 miles (9.6 km) long. The host gneiss is highly foliated, intensely folded and contorted. The weathered cordierite was described to have dark brown surfaces that yield to blue or bluish gray massive material on fresh surfaces. I was able to obtain small samples of disseminated cordierite along the margin of this deposit. All of the cordierite was very high-quality gem material. Massive portions of this deposit remain unevaluated for gems and may represent the largest, colored gem deposit in the world. This is likely the same deposit described by Sinkankas.
The deposit is described to be scattered over a few square miles in lenticular to tabular masses in low ridges of metanorite 5 miles long and 0.25 to 1 mile wide. Some exposures are described as having 60 to 80% cordierite. It was estimated that the combined deposits with strike lengths of 100 feet or more, contained >453,600 tonnes of cordierite In other words, a potential resource of 2.27 trillion carats!
Sinkankas (personal communication, 2002) indicated that much of the material was gem-quality (Sinkankas, 1959, 1964). This (along with Grizzly Creek) could be one of the greatest discoveries of colored gemstones. To visit this deposit from your computer, fly to: 'Ragged Top Mountain, East Albany, WY 82072' on Google Earth. While you are in the area looking at the foliated anorthosite-syenite complex, note that iolites are scattered over this area and to the southwest is a distinct group of lakes that line up (structurally controlled) with what may be some carbonate salts in the soils. These are great candidates for undiscovered diamond deposits that are known as the Horse Creek Lakes cryptovolcanic structures.
Another iolite deposit in the northern Laramie Mountains is referred to as Owen Creek (Hausel, 2009). This contains kyanite, sillimanite, cordierite & relict staurolite in pelitic schist & remains unexplored. Cordierite is also reported at South Pass (Hausel, 1991), Copper Mountain (Hausel and others, 1985), in the Sierra Madre, and in the Powder River Basin. The cordierite occurrences at South Pass were investigated by me during field mapping of the greenstone belt. I did not observe any gem-quality material there. However, I highly recommend investigations of cordierite at Copper Mountain as this supracrustal belt contains abundant metapelite (alumina-rich rock) that was subjected to similar metamorphic conditions as the Elmer’s Rock greenstone belt. For more information, see Hausel (2009a, 2009b, 2009c).
How To Find Iolite
First you need to take me (just kidding). I love to hunt gemstones & I have a nose for finding iolite.
When you find iolite, it may look like this outcrop at Grizzly Creek. Note the rusty stain on the gemstone. When you break off the rust, a deep sapphire blue color may be exposed. This one outcrop easily contains a few hundred thousand carats of gem-quality iolite just within the photo. Multiply 200,000 carats by $25/carat (average value per carat) to get an idea of the value of this rock. However, iolites typically range from $15 to $150 per carat - a value that likely would be increased with marketing.
Iolite is found in amphibolite-grade metapelites (mica rich rocks). Typically it occurs where the rocks have been subjected to high pressures & temperatures that reached the alumino-silicate triple point (nearby rocks contain kyanite, sillimanite & andalusite). It is also found as a replacement mineral in some syenites and anorthosites. Few people know how to recognize this gem.
What I found is not only the largest gemstones, but also the largest colored gem deposits in the world. You would think that this would attract some interest. Visualize this. Iolite sells for about $25 to $125 per faceted stone. It can be faceted for about $0.50 a carat. Gems of iolite larger than 12 carats are unheard of on the world market. It doesn't take a nuclear physicist to see the potential here. If one were to harvest all of these iolites and sell them, we could just about pay for our national debt.
And there are likely more iolite deposits in this region. But someone has to look.