Tag Archives: opal

The Rare Gem Series: Black Opal

Imagination time! Put yourself in the stirrups of a Pony Express rider galloping across the Northern Nevada high desert. You stop at a creek in a pristine oasis known as Virgin Valley to give your horse a drink when you glance down to see an iridescent, magical, alien stone that must have come from space laying on the ground.  Curious, and somewhat confused and scared, you pick it up and feel the weight of it in your hands.  The stone is dark and smooth, and as you turn it in your hand it plays with the light.  Fires of bright colors flash and disappear.  Entire rainbows sear their spectrum into your brain.  You lose track of your objective and why you’re here.  This amazing stone has hypnotized you.  You are lost with out it.  Your past no longer exits.  You cannot envision a future without it.  It’s possession is your everything. It is your precious.

This is was how the black opal was discovered.

That’s a lie.  This is the myth created by the Nevada Tourism Board of how the black opal was discovered.  The truth is that the Pony Express followed the routes of the Oregon trail far to the North and the California Trail far to the South.  Also, the Pony Express only lasted 18 months, from April 3, 1860 – October 24, 1861.  In reality it was probably some ranch hand, or ranch rider that discovered the first black opal about forty years later in 1900, and his response was probably more along the lines of, “What the fuck is that?”

"What the fuck is that?" image from goldnuggetwebs.com
“What the fuck is that?” image from goldnuggetwebs.com

Lightning Ridge, Australia has a more gruesome beginning.  The town in New South Wales near the border with Queensland got its name in the 1870s when some passersby discovered the bodies of a rancher, his dog, and some 600 sheep all of whose hearts had basically exploded from being struck by lighting.  That’s something to put on the old “move here” brochure to promote your town; except that is also probably a lie, but a badass one at least.

Halfway across the world from Virgin Valley, in 1902, Charles Waterhouse Nettleton, a struggling opal miner from White Cliffs in Eastern New South Wales, migrated North into Queensland in search of his own strike.  He struck out.  Pretty much like he had every other time he tried his hand at prospecting.  Nettleton, defeated but ever the optimist, and since he was a stoic, kept on chuggin’ along.  He decided to walk the 400 miles back to White Cliffs, and on his way back Nettleton stopped off in Lightning Ridge and camped with the Ryan family .  The family showed him some freaky black stones that flashed color.  Nettleton recognized them as opals, but like nothing he had ever seen.

With nothing else to do (or lose) Nettleton gave a shrug and dug a big hole.  He set up camp and sunk his first shaft on October 15th, 1902.  Yeah, Nettle didn’t find shit.  Again.  Not to be deterred, Nettleton moved his camp and sunk a second shaft in 1903 and struck pay dirt.  Tens of pounds of the crazy black stones ranging from a carat to a hundred carats in size came tumbling out of the walls of Nettleton’s mine.  The hill where he made his strike is known as Nettleton Hill today.  Excited from his success Nettleton made his way to Sydney (over 350 miles by foot!) to show the stones to a jewel dealer who was not as impressed with them as Nettleton was, and only offered $1 for the lot.  “Well, fuck that,” said Nettleton, and in November 1903 Nettleton walked back to White Cliffs (remember, this is another 503 miles BY FOOT) where he knew there were people who where knowledgeable and could give a good price for his opals; unlike that dickweed, suit-and-tie pissant in Sydney.  On November 11th, 1903 an opal merchant in town offered him $30 bucks for his lot. “Oh hells yeah!” said Nettleton (or whatever the backwoods, Australian-hick equivalent would be) and sold them right there.  Think about this, Nettleton was a brute; he had dug several giant mine shafts (by hand), walked over 1,800 miles, and for his two years worth pain and struggle was psyched to be given $30 for his life’s work.  Stoics, what would this world be without them?

The connection had been made.  The opal dealer started sending his partners to Lightning Ridge to purchase large quantities of the stones.  The rush was on.  Nettleton was a hero.

A beautiful full-spectrum harlequin black opal from Richard W. Wise at rwwise.com
A beautiful full-spectrum harlequin black opal from Richard W. Wise at rwwise.com

By this time Australia had already become the opal capitol of the world with strikes in White Cliffs, and the boulder opals of Queensland.  It didn’t hurt that Queen Victoria loved the stone, and soon after Nettleton’s first rich strike in Lightning Ridge opals were discovered in Andamooka, and Coober Pedy, Koroit, and Minitabie.  While these stones are beautiful, nothing except the stones from Virgin Valley, NV and Lightning Ridge were truly black bodied.

The first big mines opened in Virgin Valley in 1905.  The first big mines opened in Lightning Ridge in 1905.  The rock that forms the area around Lightning Ridge is sandstone from the early Cretaceous Period that formed a shallow sea.  Not only are there opals there but important fossils dating back some 110 million years… Then again, the opals are fossils themselves.

What’s that?

Oh yes, opals are fossils.  What happened was that there was a volcanic eruption from somewhere nearby that coated the area in silica-rich ash.  If a creature or a plant kicked the bucket while in a puddle of water and got coated with ash, the water and ash worked together to preserve the dead critter/plant.  Over millions of years (likely) the silica combined with the water to replace the cellular structure of the organism with opal.  Opal is just a combination of water and silica creatively known as “hydrated silica”.  SiO2 is quartz, SiO2nH2O is opal.  Volcanoes pump out silica during an explosive eruption, if that silica ash buries something wet there is a good chance opal may form.  The water content of the black opals from Lightning Ridge is about 5% making them not likely to craze or crack when unearthed from drying out.

In Virgin Valley it is a different story.  Around 16 million years ago there was a series of volcanic eruptions of rhyolite that lasted for darn near two million years.  These eruptions spit out all sorts of silica-rich ash and the volcanic rock formed a series of hills that encircled an ancient basin that geologists named Canyon Rhyolite.  These volcanic eruptions are no joke.  Once the mountain goes *boom* a superheated blast of air and ash can travel across the region at hundreds of miles per hour killing everything in its path.  Combine this with a few hundred feet of ash covering the Earth around the volcano, and nothing survives.  Nothing.

Canyon Rhyolite, since it was a basin, held a series of lakes and ponds where critters flourished in a rich forest dense with ginkgo, sequoia, spruce, hemlock, birch, cedar, larch and chestnut.  The region was spared from major volcanic events for about four million years when a jerk of a hotspot decided to flood almost the entire region of what is today the Northwestern United States with flood basalt.  This buried Canyon Rhyolite under a dense, solid layer of lava that solidified above it.  Over the course of the last ten million years hot springs began to bubble up through the Earth yearning to break free.  With the hot trickles of water came bits of that silica-rich ash that permeated the buried remains of the lush forests of the now vanished canyon.  What did we just learn about the combination of silica and water?  You guessed it; opals!

The hot spring squirted through the basalt and started dribbling downhill.  Today that hot spring has carved quite the path and formed what is we know today as Virgin Valley.  Along the Valley’s walls, at about the 5090ft level you will find a layer of moist gray clay.  This marks the floor of the ancient forest.  The clay layer may vary from a few inches to a few feet thick, but here is where you will find your opals.  Petrified wood, opalized tree limbs, even the teeth and skeletons of forest creatures preserved forever as majestic hunks of gemstone.  A pretty noble way to go if you ask me.

When I die, I want someone to lay my carcass down in a bog next to an erupting volcano so that maybe, someday, several million years from now I can be dug up and brutally bandsawed and then ground down and polished into ornamental pieces of jewelry for some rich housewife.  A boy can dream can’t he?

The problem faced with many of these Virgin Valley opals is their extremely high water content of 20%; much higher than that of their Australian counterparts.  This makes many opals gorgeous but notoriously unstable.  When these opals are unearthed the majority are placed into containers of water to keep them from drying out.  When an opal dries out it crazes (forms cracks), will loose it’s dark color, and quite often will explode!  Some apply sealants to the stones to retain their water content, some just roll the dice and dry them out and hope for the best, but most just keep them submerged.  While it would be awesome to have a nice large, dry Virgin Valley opal, putting a $100,000 stone in the sun in hopes of it not exploding or just fading into a $10 rock takes some serious balls.

A Virgin Valley black opal being preserved in water. nevada-outback-gems.com
A Virgin Valley black opal being preserved in water. nevada-outback-gems.com

Throughout Ethiopia new opal fields are being discovered almost every year.  These precious opals may have white or blue bodies, and some even chocolate, but the black bodied opals resembling those of Virgin Valley or Lightning Ridge haven’t materialized in the numbers hoped for, or possibly at all!  That doesn’t mean they haven’t been sold.  A process known as “smoking” is putting lower quality crystal opals into the market and trying to pass them off as the elite black opals.  Essentially, the tricksters are taking normal light bodied stones and “smoking” them until the soot permeates the interior of the stone’s matrix.  To the common eye they look amazing, but in the long run, the stones are more likely to crack, pit and fade than the real deal.  Just don’t pay a bunch of money for a black Ethiopian opal just yet.

Other black opals discoveries have reportedly been make in Indonesia (but some of those stones have been “smoked”); with two recent discoveries in central Wyoming, and along the North Fork of the Snoqualmie River in Washington State!  With the incredible ash fallout that originates from hotspot volcanoes like the Yellowstone Caldera and the Long Valley Complex in California I would surmise that there are thousands of undiscovered sites for precious and black opal from Wyoming through Colorado and Nebraska; and in California, Arizona, and Mexico.  Get hunting!

I know, you just read a ton of words and all you want to know is, “what are they worth?” Fine.  A precious black opal with small blue/green shifts in color covering about 50% of the stone will get you about $200 per carat.  The more of the stone that is iridescent, and the larger the color flashes are, and the more of a red/green shift those stones have the more money they are worth.  A stone that is 90-100% covered in red/green flashes, with a black body, can expect to sell for upwards of $5,000 to $10,000 per carat.  These are among the rarest fine quality stones in the world, so keep your eyes out for fakes!  Fakes may include treated or smoked stones; doublets and triplets (stones that have a thin veneer of actual opal glued to the outside of an otherwise boring stone); as well a created matrix opals (stones that are the shavings and cuttings of larger opals that are then glued together using resin); and synthetic stones that are made of weird space-aged polymers and shit.  Just don’t get screwed.

Some helpful guides from OpalAuctions.com:

Black Opal Grading Chart from opalauctions.com
Black Opal Grading Chart from opalauctions.com
Types of black opal from opalauctions.com
Types of black opal from opalauctions.com

Hunting for the opal of my eye.

July 19th.

We awoke around seven am, in our camp off the side of a Wyoming highway. I received a voicemail from Jon Grolez telling me that he and his parents were on the dusty road which would supposedly lead us to opals. Houston, Erik and myself packed our cots and our tent, and got underway. We joked, with painful truth about the fact that the truck went through about an eighth of a tank of gas as we climbed a nine degree slope in the highway. However, the truck clawed its way up, probably over a thousand feet. We reached our target dirt road and drove for a mile inland before deciding to abandon our decidedly non-four wheel drive trailer. We parked our darling little, baby blue, white campered, broken windowed, rust flecked trailer, on the side of a dirt road. It looked remarkably natural.

Unencumbered by trailer, we blasted along a few miles faster than we should have. The dirt road would have been remarkably smooth, if not for the enormous pair of tire ruts. Those ruts, in some cases probably a foot deep, insisted on grabbing our tires and making for a very shifting and shuddering ride. In all the drive was still quick, and the call of the opal had us all excited. We caught up with Jon and his parents, Ned and Brenda, after about twenty minutes. The had stopped near a small gas well and prospected for some small stones. They had also managed to wrangle a horny toad, which to someone who has only seen them on television, was remarkably small. Likely the altitude and Wyoming winters contribute to that particular physical trait. After conferring with Jon and family, and scouting via the truck’s GPS navigator, we set our sites on a promising set of roads and ventured onwards.

Since the land we were searching is an established gas mine, we had our hopes set on finding the road cuts which the gas company had created to install and maintain their gas wells. Those cuts we hoped would have uncovered a wealthof large opals. After another ten minutes of driving, we spotted a well with a road cut! We followed the twisting road to the well and parked at the bottom of a machine made earth slip around forty feet high and twice as wide. It was mere minutes before Jon’s mother, Brenda, found our first opal encased in a larger stone. A few more small opals were found as we scoured the road cut. Eventually a white truck pulled up and a maintenance man for the Gas company asked us what we were after. Unfortunately, I personal was up the slope hunting for my own opal, and did not hear the conversation. What I did see were handshakes, gestures towards some of the other buildings and wells visible from our position, and Houston, hopping into the front seat of the truck and driving away. After searching for another twenty minutes or so, i worked my way up over the lip of the roadcut and followed a crease in the hillside likely caused by snow melt. I found a number small embedded opals along with an interesting geode, which Houston dubbed ‘hillbilly teeth.’ By the time I had turnedback down the hill with my handful of stones, the white truck had returned with Houston. Houston hopped out and quickly transferred a large stone from the bed of the company truck, to the tailgate of his. Dwarfing my own collection of interesting stones, was an opal laden stone, probably around forty pounds in weight, which will be cut and polished upon return to Seattle. Ned, Jon’s father, turned to me and said, “Uh oh, has opal fever caught you too?”

“Why of course!” I replied, “I had it before this trip ever started!” From subsequent conversations, I learned that the gas company man, a regular maintenance worker on many of the wells in the area, had picked up plenty of opals and was able to take Houston to a recently excavated area. It was at that area that Houston was able to claim the prize stone of our trip. After that stone dwarfed, by far, anything we’d picked up on our first stop we decided to move and look at other sports. We drove past some wells which had warning signs for Di-hydrogen(? H2S) Sulfide and smelled intensely of sulfur egg farts to another promising road cut. Our luck after an hour or so was limited. The most interesting part of the stop was finding a wash point which was filled with small rolled and colored stones. It was similar to digging through the numerous bins at a rock shops to pick out a handful of interestingly colored stones for a few bucks. The location, in the bright Wyoming sun, overlooking the rolling hills of sage, crouched into a jumbled pond of stone, and catching the occasional wiff of egg fart, was much, much better.

We realized, finding a monster opal in that area would require some major heavy equipment and test trench after test trench. So we decide to backtrack and find a way out to an untouched hill off in the distance with clearly visible eroded cliffs. Another twenty minutes of bouncing along dirt roads cut through sage brush, we got as close to the hill as we could. By this point, a few hours into our adventure. Erik, Houston and Myself were lamenting the fact that we had left almost all our water, and the gigantic ‘manwhich’ that was our lunch, in the trailer we had abandoned miles away. Fortunately the Groelz’s took pity on us, and fed us an enormous mound of watermelon.

After fortification with fruit, it was about a ten minute walk from our cars to the bottom of the hill. Another five minutes saw us up the side near the cliffs which had looked so promising from a distance. We all complained about walking uphill at altitude, though physical fitness level might possibly have been a culprit. We split up and covered nearly the entirety of that large mound. Unfortunately, our search of the hill was fruitless. For myself, lust of the eye kicked in and I became more focused on reaching the summit than I was on scouring the earth for opals. The view from the top was striking. The wind was whipping so powerfully that i was forced to abandon my hat, held down by the head of the pick I had been carrying. I spent a good amount of time on the summit, splitting my attention between the ground and the view spreading in every direction. I found a US Geological marker from 1948 pegging the altitude around 7500 feet. As I searched a section of the summit which looked promisingly dug by wildlife, a large hare jumped from cover. It raised a white tail and skipped away, disappearing over the edge of the hill. Although sighting a hare might be trivial to someone from Wyoming, or anywhere else for that matter, it has maintained a prominent spot in my memory of that day. Prior to my accent up the opal-less hill, I had spoken with Brenda about the scale of the landscape and the differences of continental geography compared to that of my home islands. Now, in hindsight, I find that those small things, such as hares and horned toads, which exemplified the differences I was observing, have stuck prominently in my mind. Of course, having already found a forty pound opal, hiking up a hill on a beautifully sunny day with seventy degree weather and blasting wind, make a pretty good impression on their own.

As I noted, our success on the hill was limited. There was hope that one spot which Jon had spotted might contain nice brown opal, but this was not the case. The only success was my own. After hacking into the side of the hill for a short time, we determined Jon’s site had no opal. As I reclaimed the hat and bucket I had set a few feet away, I found a relatively large shard of brown opal sitting on the surface. We looked around briefly but could not discover where it might have originated. However, we had already decided to change spots, and Ned and Erik were nearly back to the trucks. So we clambered back down the hill with our single opal shard. Returning to the truck, we decided to continue on the road we had followed to our hill. The road was nothing more than a discoloration caused by a pair of semi-visible wheel cuts through the sage brush, it wrapped halfway around our hill and looked to cut back towards another more obvious road. We followed the bouncing path, through a couple herds of cows, and past a large herd of pronghorn antelopes. Unfortunately we misjudged our bouncy rut of a road and wound up right back where we started – next to the first roadcut and the fart wells.

We decided to press on in the opposite direction, having just made a giant circle. What a choice. We found another relatively fresh road cut, and a recent construction project. This final site was the jackpot. “Oh, there’s one.” was the first thing out of my mouth as I stepped from the truck, and everyone seemed to repeate that statement every other step. Most of the opals were embedded in host rock, and many more had begun to change colors in the sun. We did realize however, that to take the opal laden boulders which we found the most impressive, we would need a flatbed with a crane. Our last stop lasted a long time.  We continuously picked up promising opal stones, only to promptly drop them for more promising stones. Eventually everyone found their choice examples to take home. Around three pm the Groelz family decided it was time to get on the road back to Utah, and we had decided it was time to find our trailer which held the promise of an enormous ham sandwich. We said our goodbyes, piled into our respective vehicles and followed the now familiar dirt roads out of the Wyoming hills.

After stopping to reattach the trailer and to eat a sandwich so full of ham it made our jaws hurt, Houston, Erik and I worked our way towards Wheatland, Wyoming for our next stop. The initial plan was to stop and camp somewhere and finish the drive in the morning. But fortified by caffeine and wondering if we would outrace the thunderstorms over Wheatland we ended up pushing into the hills. We followed a four wheel drive trail until we reached a section of road flat enough to pitch our tent. We did so, cursing the clouds of flies and mosquitoes which were drawn to our headlamps and open mouths. It was too late to cook dinner, but the sheer number of bugs I swallowed managed to tide me over.

Erik and I poured two fingers of celebratory whiskey. Some nice Glennfiddich scotch, which we drank from the sawed off bottoms of twelve ounce water bottles. Fortified, we settled down to sleep and dream of man sized iolite…  That is to say, sleep as well as we could in a tent which repeatedly tried to pummel us to death through the night.

Again, any errors are my own, including such things as maybe using the wrong or multiple names for Jon’s Mother. Sorry.