by Don Thompson
Photos by the author.

In search of East Africa's eye-catching Maasai sunstone.

Above: Masai boma, 30 miles west of Mt. Meru, and Arusha, Tanzania.

Examining a day’s recovery of sunstone.

One rough and one cabbed sunstone.

Future Tanzanian gem dealers.

Tanzania in East Africa, sits astride one of the most prolific gemstone belts on the planet. Nearly every known natural gem can be found within its borders. Some gems, such as color-change sapphire and garnet, chrome tourmaline, and the better-known tanzanite, are found nowhere else in economic quantity. The lure of astounding gems attracts many adventurers, and the country's good (by African standards) and improving political system help make Tanzania a fun place to visit.

The country's gem trade thrives in the town of Arusha, in the north central part of the country. Situated on the southern flank of Mt. Meru, a smaller but yet immense volcanic sister to Africa's tallest peak, Mt. Kilimanjaro, which lies about 60 miles to the east, Arusha enjoys a beautiful climate, friendly people, and lots of opportunities for gem buyers. A major rallying point for tourists set on climbing Kilimanjaro or exploring the Serengheti or one of several other national parks close by, the town was once a favorite hangout of Ernest Hemingway.

One of my favorite pastimes in Arusha is to sit in gem dealers' offices and watch local miners and traders show their parcels of rough and cut gems. Frequently, "runners" tout stones for sellers too busy to visit all the dealers' offices in town — there being more than 100 registered gem dealers in Arusha. During past visits, I have been shown everything from nearly flawless 120-gram tanzanite crystals, proudly displayed by young millionaires, to broken windshield glass being hawked by street boys. I have seen exquisitely dressed African ladies selling 20 kilos of graded tanzanite, old men flashing a handful of two- to four-carat faceted tsavorites, bags of acorn-sized rhodolites, and 30 grams of flawless and chunky chrome tourmaline rough. Sapphire is commonly seen and tanzanite — generally very expensive — is to be found everywhere. A seemingly endless and always fascinating parade of characters come to Arusha to sell. A small parcel of valuable stones carefully rolled up in a handkerchief, stuffed into a shirt or under a blouse, or perhaps several kilos of some kind of opal found on some farm 300 miles away, carried to town on a roaring diesel bus in an old leather suitcase, and overflowing from an old, worn-out paper bag. In some offices, certain determined sellers or runners are seen repeatedly throughout the day, showing new stones or parcels on successive trips, hoping that he or she has finally found just what the buyer is looking for. I admire the drive and perseverance of these entrepreneurs. A successful sale brings a decent commission to these hard-working folk who obviously enjoy the world of stones. In the past four years, cell phones have improved the efficiency of it all, and it seems as though everyone in town is in the business. Doormen, bartenders, taxi drivers, waiters and, of course, a multitude of unemployed folk constantly try to make a few bucks selling stones.

Legally, stone transactions must be concluded in the presence of a registered gem dealer. Purchasing stones on the street without a dealer present is very risky. Foreigners carrying stones without proper documents risk arrest or confiscation of their stones. Acting as an arbitrator between buyer and seller, a good dealer will help the buyer with his negotiations and keep the sellers honest by noting defective stones. Dealers don't want most stones to sell at overly high prices because the sellers will expect to get similar prices from the dealers after the buyers have gone. Instead, a wise dealer will watch his buyers' buying habits, learning which of the many available stones are marketable (besides the common but overpriced tanzanite). The dealers will then buy those stones as they become available and hold a variety of them in reserve to show and sell at a good profit to future buyers. Many dealers gradually compile parcels for themselves that they later carry to Europe, the United States, or Asia for resale.

At times, when sitting in a dealer's office, and only inferior lots are being offered, it is the anticipation of eventually seeing something of value that keeps everybody's interest up. Patience really becomes a virtue for anyone traveling to Arusha, because great stones are available. Travelers should plan on staying a while, enjoying the scenery, food, drink and, of course, the stones!

Dealers expect a negotiable two percent or greater fee for their services, to be paid after the buyer's parcel is packaged and sealed in front of the government agent. This sealing process must be done properly to prevent the confiscation of the stones at the border or the airport. Unfortunately, not every dealer is competent when it comes to the process paperwork, and therefore it's definitely best to set aside a full day for completing the paperwork. Have the dealer arrange an appointment with the agent well in advance. The government man will calculate a very fair tax and add his fee, or "lunch money," to the bill. Of course, only the official government fees will be invoiced. The agent will provide the necessary paperwork and explain the procedure for presenting it at the airport. An honest dealer will hold the sealed parcel in his safe until it is time for the buyer to leave the country; at that time the buyer can pay for the stones and the dealer's fee and receive his parcel, still sealed, thereby reducing his or her risk of theft.

Internal platelets or "spangles".

Called "flowers" by African miners, variably sized thin transparent flakes, or platelets, make Tanzanian sunstone eye-catching.

1.46 ct. highly included round brilliant, cut by the author.

A New Stone?
During one such trip, my friend, Eileen Shelton, and I sat in the office of Paul Kaje, a licensed gem dealer and Pentecostal minister, as his fellow pastor and gem-dealing friend, Longan, ushered in, one by one, hopeful stone salesmen. (For some reason, many protestant pastors moonlight as gem dealers in Tanzania.) Fortunately, the day in question proved worthwhile when a miner, a parishoner from Longan's church, entered Paul's office. As the Tanzanian miner poured his rough stones onto the dealer's desk for us, red and orange flashes jumped out from the tumbling mass. As we slowly rotated and examined individual pieces, flat transparent flakes within a clear matrix flashed neon shades of orange, green, blue, pink, and lavender. Eileen and I had seen many examples of Oregon sunstone but we realized that these stones were very different.

That, our first exposure to the new vivid East African sunstone, was in May of 2002. Unknown to us at that time, parcels of the stones had already been finding their way into the American market for over a year, with prices of rough and cut stones fluctuating wildly as dealers and buyers maneuvered to establish values for the new material.

Upon returning to Montana, I faceted and cabbed three dozen of the stones, which I showed to Bill and Barbara Bowden at the Denver gem and mineral show in September of 2002. The Bowdens, from San Antonio, Texas, owners of Rocks, Lapidary, and Jewelry, were amazed by the new sunstone's color antics. Looking like molded acrylic gumdrops filled with colorful confetti flakes, or "spangles," as Bill called them, the clearest of the cut stones frequently produce comments of disbelief from experienced cutters.

Floating within a pale green to colorless feldspar matrix, variably sized thin transparent flakes (Bill's "spangles") are aligned parallel to cleavage planes. Local African miners call these euhedral flakes "flowers." The transparent (hematite) flakes are predominantly orange, gold, or red-orange. However, they reflect a multitude of electric neon colors as the stones are rotated. Heavily included cabochons frequently display one or more cat's-eye bands and weak starring is occasionally seen. Finished stones of 20 to 120 carats are not uncommon. Light green matrix stones, initially misidentified as emerald by African miners, have few or no spangles. However, it is within the colorless matrix that the fascinating flat inclusions are most frequently found. Surface striations seen on occasional colorless matrix pieces, as well as laboratory analysis of the sunstones, identifies them as being plagioclase feldspar.

As with any gemstone, few pieces of the new material are of top quality. Cleavage problems and impure matrix makes many of the stones unfit for fine faceted gems or even cabochons. This lower-grade material is doomed to become beads or fish-tank gravel. On better stones, attempting to polish facets parallel to cleavage planes can be difficult, requiring the use of a wax lap. However, the spectacular flashing colors so well presented in small and especially large well-cut and competent-bodied gems make sorting through a relatively large volume of rough material well worth the effort.

Dubbed "Illusion Sunstone" by New Era Gems' Steve Ulatowski, and "Tanzasun" by Bill and Barbara Bowden, the new material could perhaps be given the more fitting name of "Maasai Sunstone." Found first by a young Maasai man on tribal grazing lands in about 2000, the stone's basic color, red orange, mimics the bright hues of the Maasai people's dress. Since the Maasai have found several of East Africa's gem deposits, it seems fitting that at least one of their stone discoveries should carry their tribal name. (During many visits with the Maasai, I have learned how important the red-orange or copper color is to them. My partner's Land Rover is a red to bronze color. Without fail, upon our arrival at any Maasai village or boma, the Maasai will immediately begin admiring the color of his car and, much to his chagrin, immediately begin writing in the dust covering his vehicle!)

150 cts. of Tanzanian sunstone, looking like molded acrylic gumdrops filled with colorful confetti flakes.

The spectacular colors so well presented in even small gems make sorting through a relatively large volume of rough sunstones well worth the effort.

Sunstone on site.
My return took longer than I expected; I was unable to return until 16 months later, rather than the promised four. When I did get back to Tanzania in October, 2003, I visited the sunstone mining area with my Arusha partner, Sune Merisheki. For two years, dozens of miners had intermittently worked two deposits separated by seven miles of GPS-measured, rough, brushy terrain.

At both locations, nearly identical geological environments were pockmarked with numerous pits, shafts, and short adits. Exposed in canyons at each location were moderately soft, well-foliated biotite schists, 80 feet or more thick, overlaid by very hard granular quartzites and quartz gneiss. Large volumes of slope rubble and float rock covered the hillsides, in many places hiding the contacts between the two rock types. However, at both locations, the foliation of the schist is parallel to the schist/quartzite contacts that were visible. Six-inch- to four-foot-long broken lenses of white to pink feldspar lay pinched in and parallel to the schist foliation. The sunstones were found within these sugary feldspar lenses and pods. At neither location was the base of the biotite schist exposed, so we were unable to determine either the schist's thickness or the preferred stratigraphic position of the sunstone-bearing lenses within.

Our visit to the first, or western dig, began at a Maasai boma — a settlement of about 50 hearty souls living in the small, grass-roofed wood and mud huts surrounding their cattle corral. This boma was one of three temporary satellite settlements or extensions of the nearby central village. Each boma was the equivalent of a Montana "cow camp," and tribal members — usually very young boys — would drive cattle from the bomas to nearby pastures. The corral and its human shelters were all surrounded and protected by the nastiest of thorny acacia branches heaped in a lion-deterring doughnut about 15 feet tall. During the night, a similarly thorned gate would be pulled tightly shut against the normally open entrance.

After sharing cordialities with the folks at the boma, we headed for the mine along a two-mile road hewn through the woods by the locals and miners. Winding along the "road" through dried forest, steeply angled creeks, and long, narrow rocky ridges, we finally arrived at the mine. Two adult giraffes grazing in the forest just above the digs seemed to be standing guard. Within the outline of a miner's abandoned stick shelter lay the dried skin of a snake, no longer of use to its former owner. Still exposed in the digs were partially excavated feldspar lenses, many yielding flashing gems when challenged with the hand pick. The five-acre site had been mined hard, with tons of broken schist scattered over the area, covering most of the virgin ground that remained. After taking samples, photos, and GPS readings for several hours, we drove back to the boma where we learned that a woman there needed medical attention, so we drove her back to the main village. By then it was too late to visit the second site, so Sune and I got rooms at a nearby guesthouse.

Early the next day, we drove to our second mine site kickoff point, a small village where we would leave the car and pick up a guide for the three-mile hike to the dig. We were escorted to the second dig by a young Maasai man who was to fend off any hungry lion we might meet. While it is said that African lions steer clear of the Maasai, I was a little distressed to see that his defensive weapon of choice was a slender but well-polished stick! We headed in, eventually passing a second boma, housing even fewer people than the previous day's. As we passed by, we were overtaken by two lovely girls on their way to tend their cows on the mountainsides above the digs. The girls were dressed in amazingly clean blue Maasai robes, wearing traditional large, flat, platelike necklaces formed from circular rows of multicolored beads. Their silver earrings hung like delicate mobiles which jingled in the breeze like miniature wind chimes. The beautiful girls laughed at their unexpected visitors and spoke with Sune for a few minutes in kiswahili, the predominant language of East Africa. The girls eventually walked on ahead, passing our guide, who patiently waited for us to catch up.

6.64 ct. Tanzanian sunstone, "Blue Ice" design by Jeff Graham, cut by the author.

Upon arriving at the eastern digs, we discovered that the schist here was exposed over an area exceeding 50 acres. The excavations here were more complex, with a greater number of larger and deeper adits and shafts. Several tailings piles exceeded 50 cubic yards in volume. The soil horizon was thicker here also, with more vegetation growing on the weathered schist outcrop. We met one young miner here who camped at the nearby boma at night. He showed us his digging hole and later, back at the boma, proudly displayed a large parcel of sunstones, which we purchased.

After sampling, photographing, and mapping the second area, occasionally hearing the cowherd girls laughing somewhere on the hillside above us, we trudged back to the Land Rover, my small backpack straining under the heavy load of sunstones. As we walked back along the same trail by which we had come, I was attracted to the large number of small obsidian arrowhead flakes scattered along the path, artifacts left by countless previous inhabitants of these hills. How many thousands of people had crossed this sunstone deposit over how many thousands of years, not knowing or caring what lay beneath their feet?

13.32 ct. antique square cushion cut.

My wandering thoughts were suddenly brought back to the present when our guide pointed out the fresh lion tracks headed back out atop the footprints we had left while walking in. We were following the lions back to the car! Filled with new energy, we marched quietly but quickly to Sune's Land Rover, all the while scanning the thick brush on either side of the path, hoping not to spot our unwelcome guest — or was it we who were the guests here?

On the horizon.
Viewed as parts of a whole, the geology of the two mining areas suggest the existence of a stratabound sunstone deposit exceeding several square miles in area. That means the sunstone-containing biotite schist may lie in the earth in a manner similar to a shale or other sedimentary bed, perhaps 200-300 feet thick, underlying many square miles. Actually, the biotite schist may be a billion-year-old metamorphosed shale bed, visible in the deep creek bottoms only after the streams had exposed it through the action of erosion. The fact that the foliation, or "bedding," of the schist is parallel to the contact with the overlying quartzite supports this idea. An alternate and equally viable geological model suggests that the two deposits are disconnected alteration pipes. In this scenario, the sunstone-bearing schists would be separate and localized, the result of the action of circulating mineralized fluids controlled by faults or other conduits. In either case, additional deposits containing millions of carats of the highly prized variety of the type of sunstone found here are possibly lying just beneath the surface. Further surface mapping and three-dimensional evaluation of the feldspar lenses and alteration zones within the schist will prove which scenario is correct and will lead miners toward the high concentrations of sunstone pods which can be economically removed.

At present, fewer than half a dozen miners continue to probe the schist for more sunstone pods. Supplies of the rough stones are low, with only a few kilos being sporadically recovered. Rumors and false source reports attempt to explain the scarcity of material on the market. One such story, that the stones were being mined in Congo and had been buried beneath a recent lava flow, is typical. In reality, the haphazard mining methods of the recent past have produced sloping rubble piles that cover unworked ground, making further hand digging difficult. Also, most of the miners have not related well with the local Maasai leadership and have been asked to leave the area. An example is the case of a local miner who brought a compressor into the western digs and mined extensively until being asked to leave by a group of Maasai. It seems the fellow had rudely begun mining without first inviting local Maasai leaders to consultations over the ritual cup of tea.

I bought more sunstone material in Arusha before leaving for home. I can hardly wait for time off from work to begin cutting what I consider to be one of the world's most spectacular gems. In addition, I would like to do my part in developing a mining, cutting, and marketing plan for the beautiful new stone from Tanzania. Reactivation of the sunstone mines will require financing, scientific exploration methods, and sound mining techniques. It will be necessary to work with the Tanzanian government and the local Maasai. Bill and Barbara Bowden, owners of Rocks, Lapidary, and Jewelry in San Antonio, are presently doing a fine job of marketing most of the material I am able to collect. With foresight and luck, the "Maasai Sunstone" story promises to develop into a significant gem world legend rather than fade away as an overnight but quickly forgotten flash in the pan.

This account is a result of repeated encouragement and honest critiques from Bill and Barbara Bowden.

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Don Thompson is a geologist, lapidary, and geological consultant who operates Quest Minerals in Billings, Montana.