By David K. Joyce and Daniel D. Joyce
Nestled in Arizona’s Dripping Spring Mountains, the historic 79 Mine has long captivated mineral collectors with its rugged terrain and rich geological history. In recent years, a dedicated group of mineral enthusiasts has explored its labyrinthine workings in search of fine-quality specimens. This article chronicles several collecting forays that we’ve been fortunate to take part in, in hopes of offering a glimpse into the thrill of unearthing these treasures beneath the desert floor.
The 79 Mine was discovered in 1879 by Michael and Pat O’Brien (brothers, according to the 1929 US Geological Survey, Bulletin 771). Michael lived in a dugout near the site, the remains of which can still be seen today. Early development focused on extracting silver, lead, and zinc, with intermittent mining continuing into the early 20th century. Although small in scale, the mine’s rich and unusual mineral assemblages eventually earned it worldwide recognition among collectors.
Fast forward to 2017, the most recent group of owners formed 1879 Minerals LLC and began refurbishing the mine while keeping its workings in safe condition. Since then, they and a select group of trusted guests have collected mineral specimens from the site—we’ve been fortunate to be included among them and thank Cody and Brian Schwenk for the opportunity.
79 Mine Deposit Geology and Details
The 79 Mine exploited a replacement-type deposit composed of galena, sphalerite, pyrite, and quartz, occurring in fractures in thinly bedded limestones and shales of the Naco Formation. The ore body measured approximately 335 meters in length, 12 meters in thickness, and extended to a depth of about 152 meters. Interestingly, the sulphide mineralization targeted by miners did not contain the specimen-quality minerals that collectors prize today. As a result, very few collectible specimens were recovered during commercial operations. The most desirable minerals are found in low-grade, oxidized portions of the replacement zone that were bypassed by earlier mining efforts. Notably, we have rarely encountered sulphide minerals underground at the 79 Mine—only on the dumps.
The mine’s workings total over 3,000 metres of drifts, raises, and shafts. Commercial metal mining and company involvement ceased in the mid-1960s. Since then, numerous mineral collectors have explored the site. Tony Potucek’s excellent article on mineral-forum.com provides a detailed account of the early collecting history at the 79 Mine, which will not be repeated here.
Recent Collecting Trips
The 79 Mine is located on a private claim with no public access. The road in is extremely rough, with locked gates and trail cameras on the property. As mentioned previously, the current owners invite experienced colleagues to collect—people aren’t given access to collect solo.
Collecting typically takes place in low-ceilinged stopes where mineralization is exposed. A high-quality respiratory mask is essential, as disturbing the rock releases a lot of dust, some containing lead. Collectors emerging from the workings are covered in fine dirt from head to toe, a complete change of clothes is necessary.
Most collecting is done in previously mined areas maintained by the current owners. Essential collecting gear includes a rock hammer, chisel, hammer drill, picking tools, helmet, gloves, and knee pads, along with plenty of wrapping material. Many of the crystals—especially the aurichalcite and paper-thin wulfenite—are extremely delicate and require careful excavation and handling. Excessive jostling or poor packing on the climb back to the surface can result in breakage before the specimens ever see daylight.
Several key areas of the mine have produced fine mineral specimens in recent years:
Second Level – This level has yielded modest specimens of hemimorphite, cerussite, and wulfenite. However, no particularly noteworthy finds have been made lately.
Third Level – Hemimorphite Stope – Hemimorphite can consistently be collected here, either as crystals or in botryoidal form. While much of it is colourless or grey, excellent robin’s-egg blue botryoidal specimens have occasionally been recovered. A major new zone was discovered in 2022, resulting in dozens of flats of attractive material. Since then, smaller but still vibrant pockets of blue botryoidal hemimorphite have continued to be found.
Fourth Level – Aurichalcite Stope – This stope has regularly produced attractive specimens of aurichalcite and, from time to time, fine green smithsonite. The aurichalcite typically appears as sprays of light blue, acicular crystals nestled in cavities lined with sparkling hemimorphite and calcite.
More notably, a large cavity of some of the finest deep-blue chrysocolla ever encountered at the mine was recently discovered in the Aurichalcite Stope. The chrysocolla occurs as rich, blue botryoidal aggregates, occasionally exhibiting stalactitic forms. Many flats of exceptional specimens have been recovered and distributed throughout the collecting community. Efforts are currently underway to extend this extraordinary chrysocolla vug.
Fourth Level (cont’d)– Wulfenite Stope – This is arguably the most unpleasant area of the mine to work in, due to its high heat and humidity. As a result, collecting here is difficult, and few excellent specimens have been recovered in recent years.
Fifth Level – Smithsonite Stope – This stope has produced some of the best aurichalcite and smithsonite specimens found at the mine in recent years. Several pockets of light to dark green smithsonite have been excavated, some of which are world-class. In areas near these pockets, attractive light blue, acicular aurichalcite has also been found.
Collecting Adventures
Most collecting trips to the 79 Mine yield modest results. As with any locality, exceptional finds are rare—and the 79 is no exception. However, every so often, something exciting turns up, and we’ve been fortunate to be part of a few of those discoveries.
Aurichalcite
Back in 2018, during his first visit to the 79 Mine, David K Joyce worked away in the Aurichalcite Stope, initially recovering only poor specimens. At one end of the upper part of the stope, he focused on a vein-structure lined with sparkling hemimorphite crystals on a limonite matrix, but little else of interest. As he chipped away, he suddenly spotted an intense blue, thick-bladed, isolated spray of aurichalcite crystals nestled among the smaller hemimorphite. Working carefully, he managed to extract the spray intact on matrix. Specimens of aurichalcite from that specific spot are rare—and possibly unique.
On a subsequent visit with Ray McDougall, we opened up an aurichalcite zone in the roof of the Smithsonite Stope and managed to recover a few decent specimens. By the end of the day, we were exhausted from working overhead with hammer and chisel in the stope back, so we packed up and began the climb to the surface. We paused to rest on the fourth level, and after about ten minutes, we heard fellow collector Cody Schwenk climbing the ladder toward us. With perfect timing and a touch of drama, he emerged holding a spectacular aurichalcite specimen—recovered from the very spot we had been working, simply by extending the pocket zone another few inches!
David’s best aurichalcite experience came during a visit to the mine with collecting partner Chris Rayburn from Colorado. They focused on the same area that had previously produced Cody’s excellent specimen, along with a few more modest finds. This time, they broke into a fresh zone of vibrant aurichalcite and recovered several fine specimens, some partially coated with tiny calcite and hemimorphite crystals. David had one more particularly good “aurichalcite day” in the fall of 2024, when he discovered another small zone of vibrant blue aurichalcite on hemimorphite and calcite in the Smithsonite Stope.
Cerussite
David collected his first cerussite crystal on one of his early visits to the mine. That might not seem significant to some, but for a Canadian collector—where cerussite is virtually nonexistent due to glacial activity during the most recent ice age—it was a big deal. Shown below is a photo of the modest, elongated, twinned cerussite crystal he recovered.
He hasn’t found any noteworthy cerussite crystals since then, but he did acquire a fine “V”-twinned specimen from Cody Schwenk, which is shown below.
Smithsonite
Smithsonite is common at the 79 Mine—though much of it is ordinary grey, brown, or white and generally unremarkable. On occasion, however, David has managed to collect some small but attractive examples of the highly sought-after green smithsonite for which the 79 Mine is renowned. In late 2023, he found a small pocket of light green smithsonite in the floor of the Smithsonite Stope, though the find was limited. He has also located smaller vugs of smithsonite from time to time, sometimes associated with aurichalcite or calcite crystals.
David’s attempts to find exceptional smithsonite were modest until the spring of 2024. In April of that year, while collecting in the Smithsonite Stope on the fourth level, he managed to chisel into a new, large pocket of stunning green smithsonite. Several excellent deep green specimens were extracted from the zone. After informing Cody, the two returned to the site together and collected the remaining specimens—some of which were truly outstanding.
Some smithsonite pockets are remarkably clean, lined with green smithsonite that requires no preparation. The specimens featuring calcite crystals and occasional aurichalcite are typical of these pockets. Other pockets contain green smithsonite coated with a thin layer of white smithsonite, which can be easily removed with a quick dip in hydrochloric acid, as shown in the before-and-after photos above. These coated specimens often display tiny hemispheres of rosasite as an accessory mineral on the white surface.
Hemimorphite
Hemimorphite is arguably the most common mineral at the 79 Mine. It occurs throughout most stopes as sparkling linings in vugs, although crystals larger than about 5 mm are uncommon. Underground, under the bright beam of a mine cap lamp, the crystals can appear dazzling—but once brought to the surface, they often lose some of their visual appeal. That said, there are exceptions, with some macro and micro crystal forms displaying excellent habits.
In 2020, a large zone of blue hemimorphite was discovered in the old Hemimorphite Stope on the third level. The finest material was characterized by its robin’s-egg blue color and botryoidal habit. Many flats were collected by the mine’s owners and distributed to mineral collectors.
In 2024 and 2025, it was still possible to locate new extensions of this zone, yielding more outstanding specimens. One of the most impressive areas was found by Chad Nordhal of Colorado, who recovered several excellent pieces. Later, Cody, David, and Daniel Joyce, extended the zone further, unearthing additional fine blue botryoidal specimens, some accompanied by smithsonite, calcite, and hemimorphite crystals.
Chrysocolla
Chrysocolla has been a fairly common mineral at the 79 Mine, typically occurring as an unremarkable crack-filling or as a colourful substrate for more prominent and desirable species.
However, in mid-2024, a seam of deep blue chrysocolla opened into a cavity containing spectacular, lustrous botryoidal material—some displaying stalactitic forms or appearing as pseudomorphs after aurichalcite. This remarkable seam was discovered by Don Bouchelle and excavated by him and Cody, with help from others.
Wulfenite
As mentioned previously, the Wulfenite Stope on the fourth level is an extremely challenging place to collect, and as a result, we haven't spent a great deal of time in it. The environment is harsh—temperatures are higher, and the humidity is stifling. Within minutes of entering, you’re drenched in sweat. Adding to the difficulty are the unstable conditions: loose rock underfoot and a real risk of rockfall from above, making safety a constant concern. Compounding these challenges is the fragile nature of the wulfenite crystals themselves. They are often paper-thin and prone to breaking—not only during extraction but also during the arduous climb back to the surface, even if they survive that there's still the transit from the mine to home.
Despite these difficulties, the wulfenite from the 79 Mine can be exceptional. The crystals are typically thin, yellow, tabular, and square in form. However, some pockets have yielded more unusual specimens, including beautiful transparent to translucent "windowpane" crystals and thicker, gemmy orange tabular crystals with beveled edges. Of particular note is the aptly named “Cross Pocket,” which produced a very limited number of crystals exhibiting a distinctive cross-shaped zoning pattern at the centre. These are exceedingly rare, and only a handful are known to exist.
Conclusion
Over the years, many other minerals have been discovered at the 79 Mine, with fine specimens finding their way into collections around the world. For a more comprehensive look at the diversity of minerals from this remarkable locality, be sure to visit mindat.org and explore the detailed listings and photos. In the meantime, we’ve included a selection of additional specimens from our own collections below.
P.S. Click Here to do a quick search on our website for AZ specimens —we’ll be posting many of them, including new finds from the 79 Mine, in the coming weeks!
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