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No Green to be Seen: The Diopside Dilemma

By Bart Curren, Columbia Gem House Inc.

Tashmarine, the luscious green diopside from China that Columbia Gem House introduced in 2001, has two plusses in its favor: high brand recognition and unquenchable consumer demand. There’s just one problem. No one can find any more of this gem.

There’s green diopside, and then there’s Tashmarine—or, at least, there was.

Walking around the Tucson Show every February, and seeing literally millions of carats on display, it is easy for attendees—even gem dealers—to forget that gems are rare. We tend to loose touch with the frustrating reality of discovering and mining colored gemstones—that is, until we have to replenish supplies. It is then that even seasoned veterans remember the truth: the vast majority of gemstones occurrences are random, hard to find and seldom profitable.

These gritty lessons were driven home once again to my company, Columbia Gem House Inc., when we recently went in search of a green diopside from China that proved one of our most successful product launches ever in 2001. Introduced under the brand name Tashmarine®, the gem’s popularity exceeded our expectations and inventory quickly dwindled. Not to worry, we thought. Our decision to market the gem was based on optimistic reports from miners that the material was abundant and very likely to meet future demand. Then we went in search of those supplies and our euphoria vanished.

Great Expectations

Most gemstone occurrences are discovered by accident and often by people knowing little to nothing about gemstones. The initial strike of Tashmarine diopside in 2001 was discovered in the Tien Shan Mountains in Western China while mining for mica, a mineral with many industrial applications. The miners stumbled upon a pocket that yielded about 50 kilograms of large gem quality diopside crystals, later to be named as Tashmarine® by Eric Braunwart, President and CEO of Columbia Gem House Inc. The miners assumed that these pockets would be a common occurrence and they would be able to produce 50 kilograms per month with little effort.

In 2001, some mica miners in the Tien Shan Mountains of western China stumbled on a pocket of fabulous green diopside.

They were wrong.

Pockets of gem quality material proved to be rare. From the start, mine production was sporadic at best. Size and quantity soon decreased to nearly nothing and eventually, mining was discontinued. In 2007, Eric made the decision to send professional mining geologist Dean Misantoni to the Tashmarine mine site in order to determine if the operation warranted continued investment. I accompanied Dean as a representative of Columbia Gem House to assist him and document the expedition.

Author Bart Curren began his diopside expedition from this mining camp in the Xinjiang Uyghur Autonomous Region.

Climbing into Heaven

It was on this very cliff face that the Tashmarine mine was discovered in 2001.

Our four-day journey to reach the Tashmarine mining site took us from Portland, Oregon, to Beijing, China, then by air to Urumqi in the Xinjiang Uyghur Autonomous Region of Western China. There we caught our first glimpse of the spectacular Tien Shan mountain range. From Urumqi, it was a two-hour flight west to Aksu, China where we met our miner and guide, Mr. Wong. The flight path from Urumqi to Aksu was directly over the Eastern end of the Tien Shan range. Tien Shan translates appropriately to “Celestial Mountains”.

We left Aksu in an old beat-up Toyota Land Cruiser around 4:00 AM. After driving for a couple hours in pitch black night, the first light of dawn began to reveal narrow strips of farmland reclaimed from the barren desert of the Tarim Basin. After three to fours hours of driving on mixed pavement and gravel roads, we reached the mouth of the canyon leading into the Tien Shan range.

What started as a crude road quickly turned into a cart path. Annual floods rearrange the boulders so the path changes continually. Many times we were forced to stop, evaluate the depth of the river, move boulders or find a new path altogether. In the end, the 15 mile journey up the river valley took over 6 hours of neck- wrenching, head-banging off-road driving to reach the mining camp during which we forged 61 times on the way to the mine.

Going for the Green

In this part of the Tien Shan Range, sedimentary limestone, sandstone and shale have been metamorphosed from the intensive pressures of mountain building. In the area where the Tashmarine was found, the sedimentary rocks contain zones of mineralization created by sedimentary rocks coming in contact with magma deep underground.

The first day of our exploration began with a complete tour of the mine site. To get there involved a short grueling hike from camp, 1,000 feet up steep slopes, to the tunnels where the first few pockets of Tashmarine were found.

Author Bart Curren at mine entrance. Photo: Dean Misantoni.

Diopside was everywhere, occurring in massive seams containing crude, opaque, fist-sized crystals occurring with large crystals of mica mixed with crystals of sodalite, and what appeared to be small crystals of blue green apatite. Fantasies about new discoveries helped to distract me from the burning pain in my feet and leg muscles. So did the awesome beauty of the Tien Shan Mountains with their massive vistas.

But one quickly realizes the dangers of getting lost in fortune fantasies and scenic awe. If you want to survive on the sides of these mountains, you must constantly watch each and every footfall. There’s little vegetation, or anything else to stop one from rolling down the mountain if they slip—and this is not a place to break bones.

We continued with a 5-hour hike navigating the steep terrain around the entire mountain looking over the many prospect holes dug by Mr. Wong. We ended the day on a note of great enthusiasm and even greater exhaustion. It was all down hill from there—literally and figuratively.

All together, we spent a total of five days prospecting the immediate area around the Tashmarine mining site. The first two days were filled with optimism. On the third day, however, the low-rewards reality of prospecting began to sink in. The fourth day was nothing more than an endurance test. By the fifth day, the initial optimism of finding more Tashmarine was lost and we spent most of our time hoping for the more meager good luck of stumbling over something overlooked before.

Fording rivers and scrambling over rocks are full-time activities on a Chinese diopside hunt.

The Five-Day Learning Curve

Little evidence remains from the initial strike of Tashmarine. During our survey, Dean determined that the most likely possibility for the formation of large gem quality crystals of Tashmarine was within highly mineralized metamorphic zones, in areas where shrinkage during the metamorphic process left open cavities for large, gem-quality crystals of Tashmarine to grow. It is likely that these cavities would have later filled with calcite during the final stages of metamorphism.

Author Curren found diopside crystals but none of them were of the quality needed to justify mining.

The Tien Shan Mountains also house iolite but little of it is of gem quality.

Unfortunately, these “pockets” of Tashmarine are rare and unpredictable. It is likely that more pockets are waiting to be uncovered. But the pockets are completely random. The metamorphism of the region is of such a massive scale that the actual physical contact zones are not obvious. So it seems impossible to predict where to find them. Even though the mineral diopside can be found all around the region, the odds of finding more pockets of gem quality Tashmarine seems more remote than winning the lottery. What’s more, given the costs of mining in China, recovery wouldn’t be profitable.

Return to America

After 5 days of prospecting, it was time to leave. Our food supply had run out and we were low on bottled water. We packed all our equipment into the Land Cruiser and started the long grueling trip back to Aksu. We soon discovered that on the way in we broke the tail pipe off of the exhaust manifold. So the entire trip back to Aksu, the cab of the vehicle was filled with diesel fumes. To add insult to injury, something was wrong with the fuel injection system and top speed on the open road was about 35 miles per hour. So the trip back to Aksu took about 13 hours. I guess we should feel fortunate that the last lug nut did not fall off the wheel until after we had driven through the first small village so someone was able to bring us a jack (the jack supplied with the Land Cruiser was inoperable).

Dean and I did not fulfill our dreams of discovering more Tashmarine. But we had a learning experience for which I will be eternally grateful. The true nature of prospecting and mineral exploration is not just about new discoveries. It is about defining the nature and economic viability of those discoveries. Every once in awhile, a gem deposit proves to be rich and reliable enough to support ongoing mining. Alas, the Tashmarine mining area is not one of the lucky few. Although situated in heaven, it is not blessed by heaven.

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