Story and Photos by Paul B. Downing, Ph.D

Chrysoprase is the . green form ofchalcedony. Itresults fr~m the weather­ing and oxidation of silicate minerals, inwhich silica and nickel are released.

Chrysoprase forms by replacing de­posits of other materials, usually mag­nesite at Marlborough. The chrysopraseoccLl?s'in veins and nodules in a mag­nesite-rich saprolite zone underlying aniron-rich silica cap.

Chalcedony is an extremely fine­grained, or cryptocrystalline, form ofsilicon dioxide. Other forms of chal­

cedony'include carnelian, sard, blood­stone and flint. It has a hardness ofabout Mohs 7 and a conchoidal frac­

ture. The green color of chrysoprase iscaused by nickel oxides that imbed inthe stone as it forms.

A rare gem, chrysoprase is prized forits bright, translucent, apple-greencolor. The best material found at the

Marlborough discovery rivals the topimperial green jadeite found in Burma.For this reason, it is referred to by theChinese as "Australian jade." It is notrelated to jadeite or nephrite, however,in any way except in appearance. '

Chrysoprase was highly prized in theancient world. Alexander the Great

wore it into battle as an amulet for pro­tection and was never injured. Cle­opatracoveted it. In modern times, it issought as an alternative to jadeite. It istypically fashioned into cabochons andused in rings, pendants and earrings.Like jade, it is also carved into flowers,figurines, and jewelry shapes.

Although chrysoprase. is foundthroughout the world, including severallocations in the United States, there arethree main commercial sources: West­ern Australia, Tanzania, and the Marl-

Seeing Green in SouthernQueensland, Australia

gentle breeze rus­tles the leaves of

the eucalyptus. Abird sings in the dis­tance, breaking thesilence of this out­back world. Sud-

denly, the peace is disturbed by thesound of a boot kicking a rock. There ispause, then a thud as the rock that hasbeen dislodged is tossed into a plasticbucket. Another piece of gem chryso­prase has been found in the tailings ofthe Candala chrysoprase mine near Marl­borough, Australia.

My wife, Bobbi, and I found our­selves scouring tailings in the middle oftropical Queensland for one of themost beautiful gemstones in the world.Richard and Mary Lou Osmond, thenew owners of Candala Mine, Pty. Ltd.,had invited us over to Australia to learn

about this world-famous chrysopraselocation. Richard explained that themine had not been worked for nearly20 years. Test drilling had shown that asubstantial quantity of the gem is stillunderground, waiting to be mined. TheOsmonds have no immediate plans tomine this deposit. For the time being,they intend to exploit the large volumeof chrysoprase found in the tailings. Inpast years, rainstorms have washed thetailings to expose pieces of gem thatwere missed. There was a catch to the

Os monds' invitation: If we visited, wehad to work. Fair enough'

So there we were on the tailings,looking for chrysoprase. It sounds easy:just wander around and pick up thevibrant green stones exposed in the reddirt. Then again, things are never aseasy as they sound.

Candala MineChrysoprase

TOr:Jhry~~pr~seformsJn sealT!sor bolll.ders in a

ni~k;;l-richsaprolite zone with a'silica-rich cap.

ABqV~;Min~r~.!fhard Qsnl'ond wo.rksto removechrysopriue from a seam exposed by an open cut.

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, , A true gem chrysoprasestone seems to glow as' lightpenetrates to its translucentinterior and is reflected

back to your eye. , ,

BELOW:Bobbi found this fine piece ofchrysoprase just sitting on the surface of themine tailings.

RIGHT:Situated on the top of a hill, the mineprovides a broad panorama of the Queenslandoutback, as well as chrysoprase well worthbending over for.

borough area of Queensland. Marlbor­ough, however, is the only location pro­ducing the best gem material. Thesestones have vibrant apple-green colorwith a hint of blue that adds characterand distinguishes them from Burmesejadeite. A true gem chrysoprase stoneseems to glow as light penetrates tCrl'tstranslucent interior and is reflectedback to your eye. Changing light pro­duces subtle changes in the tone of thestone that make it an ever-changingpleasure to wear.

To mine the chrYsoprase, a bulldozermoves overburden and breaks rockuntil a seam is discovered. Then, minerspry the chrysoprase out of the rockwith hand or power tool~. Once thegem material has been removed, thebulldozer makes a deeper cut to furtherexpose the seam. In the process, somechrysoprase is missed and ends up inthe tailings material that is pushed overthe edge of the hill. That's where Bobbiand I come in.

To get to Marlborough, we flew toSydney, then to Rockhampton in thetropical coastal zone of southernQueensland. From there, we drovenorth for several hours to the tiny cat­tle and mining town of Marlborough.Marlborough consists of a few blocks oflow-lying houses topped by tin roofswith deep overhangs. This uniqueQueensland architecture is designed tokeep the occupants cool in the blister-

November 2007

ing summer heat. The social center oftown is the pub at the MarlboroughHotel. People gather after work to washthe dust out of their throats with a coldbeer and exchange the latest news withtheir neighbors. Entertainment is pro­vided by a dart board, four slot ma­chines, a television playing reruns ofMASH (when we were there), and, ofcourse, the local gossip.

The Candala chrysoprase mine is anhour's drive into the hills. As we head­ed west, the pavement gave way togravel. Gentle, tree-covered hills grewcloser. After crossing several cattleguards and passing pastures dotted withBrahma cattle and eucalyptus trees, weturned right on a narrow track. Wearrived shortly thereafter at the houseof the caretaker who protects the minesfrom unauthorized visitors. Richard,

who is known to the guard dogs, wentin to let the caretaker know we wouldbe there working for a while.

A few yards farther down the track,we crossed a small creek, entered four­wheel-drive country, and went up theslope. Richard explained that it was theonly hill in the area known to producechrysoprase. The hill is divided roughlyin half, with the Candala Mine on oneside. The other side is now owned by aChinese company and has beenworked extensively over the years viaan open cut that has removed a signifi­cant portion of the hill.

Candala's side of the hill is much lessexcavated. The mine was activelyworked in the 1960s and 70s, when itproduced the majority of the materialthat made Marlborough chrysoprasefamous. Work was stopped in the late

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TOPTO BOTTOM:

It is amazing that pieces of gem rough like this onefound in the tailings could have been missed ~y earlyminers.

These two pieces of high-quality Marlborough

chrysoprase were found exposed in the tailings of the(andala Mine.

Paul Downing (left) and Richard Osmond grade

chrysoprase rough by color, translucency, and cutting

p'iltential.

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Candala Mine Chrysoprase

1970s-not because there was no morechrysoprase, but for other reasons.Over the ensuing years, rough and fin­ished gems became increasingly rare.Fortunately, the Osmonds reopenedthe mine last year and good Marl­borough chrysoprase is now reappear­ing in the market. Majestic West Inc.(www.majesticwestinc.com) has beenappointed the exclusive North Americandistributor for this material.

Richard headed up the hill, past lowbrush and tall eucalyptus trees. At thecrest, he turned right into the miningcamp. Exiting the car, I stepped on agreen rock. There was chrysoprase lyingaround everywhere' The company hadtaken a bulk sample of the tailings andprocessed it to estimate how muchchrysoprase could be found in the tail­ings. The results were very encouraging.

Three piles of rock were left over fromthe sampling. We started examining eachmound and immediately found somegood stones. It would seem to be an easyjob to sort through the piles, picking outthe chrysoprase and discarding the rest,but mining is never as easy as it seems.The rocks were covered in sticky redmud, so the telltale green often was notvisible. A power washer was needed toremove the dirt. That became Bobbi andMary Lou's job the first day. Think of apowerful jet of water blasting the mudoff the rocks, sending muddy sprayeverywhere. Think of two ladies coveredin red mud after several hours of clean­ing and sorting. The ladies worked fortheir supper that day'

Richard had another plan for me. Wedrove a short distance down the otherside of the hill and parked. Below us wasa deep gully.Richard explained that chry­soprase from the mine tailings hadwashed down into the gully, so we weregoing down there to find it and then bringit back up the hill. The gully was almoststraight down, so getting down was notgoing to be easy,and getting back up-car­rying rocks-sounded daunting!

After scrambling down the side of thegully, we headed up through the wash.Shortly, the rocks from the mine cameinto view. Every few feet we walked, wecame upon a bright green piece. What atreat. I scoured the ground looking forgreen stones. It was like an Easter egghunt. I found stones sitting in the open,but most were hiding under water­washed banks and behind trees. Thebest piece, a thick chunk of gem green,was found partially exposed among theroots of a tree.

We hunted until our buckets werefull, emptied them, and hunted somemore. Our search produced far morestones than we could carry back up

that steep hill, so we sorted out thebest and left the rest in a pile. Gettingback up the hill was not as bad as Ithought it would be, but still a lot ofwork, especially in the near 100-degreeheat of tropical Queensland in lateMarch. As we reviewed the day's findsback at camp, however, they seemedworth the effort.

After we had recuperated and rehy­drated, Richard drove us up to one ofthe open cuts, where the chrysopraseformed in giant boulders rather thanseams. Several of these bouldersweighed up to 10 tons. They were leftby the previous miners and had recent­ly been sold and removed. As wewalked to the face of the cut, anothergiant boulder, bigger than a compactcar, could be seen.exposed in the wall.On the floor of 'the cut sat a "sma11"boulder of about 300 pounds. Vibrantgreen was visible in one section, butthe rest was mostly white. Richard toldus that all the boulders were of mixed

~ality like this. Still, I wondered howthe miners could have left so muchpotential beauty just sitting there. ThenI thought about the heavy equipmentneeded to move these giant boulders.Richard and I could not even budge thesmall boulder, so leaving them didn'tseem like such a bad idea after all.

The next day found all four of usdriving down a steep, almost nonexist­ent, rain-washed track to the bottom ofthe tailings. Again, heavy rain hadworked its miracle. Four people, buck­ets in hand, scurried back and forth likeants, searching the ground. Almostimmediately, 'I found a nice, gemmypiece. The night before, I had dreamedof finding a piece so big that Richardand I could barely lift it. I knew it washere-it was just a matter of finding it!

As the morning progressed, periodicplunks continued to echo around thewash. At one point, Bobbi called meover. There, lying exposed, was a per­fect little gem. Not big, but radiatingthe great translucent green thatMarlborough chrysoprase is famous for.Finding the stones was not always easy.Many pieces were buried in the dirtwith just a hint of green visible. Thescattering of green eucalyptus leavesmade finding them a greater challenge.Still, we were richly rewarded for ourmorning's search.

Oh yes, the big chunk of mydreams? I found it under a tree, withjust a small tip sticking out of the dirtand rubble. I worked to expose a footof surface showing a mixture of greenand white, but could not move therock. Richard and I worked some more,

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TOPTOBOTTOM:

A power washer is used to blast the tenacious

iron-rich dirt from chrysoprase found in the

tailings.

The author inspects Bobbi's special piece todetermine how best to cut it.

While chrysoprase is traditionally cut into oval

cabochons for use in jewelry, Bobbi preferred this

freeform shape for her special piece.

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Candala Mine Chrysoprase

but still it would not budge. We neededheavier tools than our hand picks, sowe decided to leave the specimen foranother day.

The afternoon found us on top ofthe open cut. Here, too, there were lotsof small chunks of chrysoprase on thesurface. There was also a seam runningdown the wall on one side of the cut.The material in the seam was mostlywhite, but one section showed a finegreen color. Richard removed a coupleof pieces of chrysoprase with a pick,but serious recovery efforts would haveto wait for heavy equipment. Weworked until the heat of the afternoonsun did us in.

The third day found us at camp,cleaning and sorting rock. Mary Louhad devised a unique way to wash thetenacious red mud off the chrysoprase.She half filled a cracked pla~tic bucketwith material. Then Richard blasted therock with the power washer. The waterand mud poured out of the cracks,leaving only cleaned chrysoprase. Thisamazingly effective technique usedvery little water, which is at a premiumon the hill, yet produced clean stones.Without the bucket, the blast of thepower washer just blew the rocksacross the ground.

The washing produced piles of beauti­ful green rock. Richard and I proceededto grade the material for shipment backto the United States. Candala's roughchrysoprase is graded based on its cuttingpotential. Premium-grade material isselected because it has a high potentialto produce the best translucent apple­green gems the mine is famous for. "/\'grade is rich green with little waste. It willproduce great stones, some of them topgems. "B" grade is the same green withwaste and/or inclusions reducing theyield of cut stones. It also includeslighter-colored or more opaque stones."C" and "0" grades have even morewaste and color variation, but still havegood cutting potential.

As we sat on chairs working throughthe piles of cleaned rock, I marveled atthe gleaming green beauty of what wehad found. Every once in a while,Richard or I would stop and just admirethe piece in our hand. Of course, we hadto share. "Look at this piece," Richardwould say, holding it up to the sun. "Oh,wow!" I would reply.

When we were done we had threepiles of rock. The smallest pile repre­sented the premium material. A some­what bigger pile was "/\' grade. The vastmajority was "B" grade. We had left the"C and "0" grade in the tailings. This istypical of any mining operation I haveexperienced.

We left Marlborough tired, but withsatisfied smiles. Visions of green wereindelibly etched in our brains. Bobbi'sspecial piece was tucked in her pocket-with the owners' and guard dogs' per­mission, of course.

After a few days back home, I wasready to tackle Bobbi's special stone.The first task was to examine the stoneto assess its cutting potential. To get abetter idea of what lay inside the stone,I ground down the dirt and matrix onthe side opposite the fractured faceBobbi saw at the mine. Doing so, I dis­covered some white inclusions and athin part. I sawed off the thin part, thenI ground the stone down to remove theimperfections.

Slowly, the stone began to takeshape in my hands. I could have madea good oval of about 16 centimeters by12 centimeters, but both Bobbi and Iprefer freeform shapes. After removingthe imperfections, [ had a roughfreeform, but it had an unattractive out-

..li"ne.I thought that it was too straighton the right side, so I gave it a fewswipes on the fine grinder. Suddenly,the stone snapped into shape. It wouldmake a beautiful ring stone and wouldremind both of us of our great trip tothe mine.

Australia is a wonderful country. Thepeople are great. They speak English,albeit an Australian version that some­times becomes unintelligible to ourAmerican ears. While the countrysidein Queensland is not all that differentfrom parts of the United States, theflora and fauna sure are. Kangaroos areeverywhere, but are seen mostly in theevening. Koalas are very elusive and areseen by tourists mostly in zoos, but thebirds are extraordinary. Parrots, galahsand cockatoos abound in Sydney, aswell as in the countryside. The mostspectacular, we think, is the rainbowlorikeet.

Bobbi and I are still seeing greenrocks in our minds. There is a specialthrill to the hunt for and discovery ofthis super gem. Chrysoprase trulyseems to glow with an inner beauty Ifeel is unmatched by any other gem­stone. Perhaps it has captured some ofthat bright Queensland sun. I neverthought I would feel about anotherstone as deeply as I feel about opal, butMarlborough chrysoprase has touchedmy heart. It is truly as special as theplace it is found. ~>

Paul B. Downing Ph.D. has been writingabout opal for Rock & Gem for many years.His best-known books are Opal CuttingMade Easy and Opal Identification &Value.

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