A collector's guide to Nancy Hanks Mine, USA: its geology, mining history and notable minerals, illustrated with the 44 specimens documented from this locality on EarthWonders.
Key facts
Nancy Hanks Mine is a compact but highly distinctive Colorado classic: a copper-gold-silver prospect in Nancy Hanks Gulch, on the north side of Unaweep Canyon in Mesa County, that later became far better known to collectors for sea-green fluorite, amethyst, quartz, barite, and calcite combinations than for metal production. Its setting is part of the Unaweep mining district, where mineralized fissures cut Precambrian granite, schist, and gneiss below Triassic sandstones and shales exposed in the walls of the canyon. The best specimens are instantly recognizable: plates and crusts of translucent to gemmy green fluorite, commonly octahedral, with pale to purple amethyst druse or quartz points scattered, layered, or sandwiched between fluorite generations.
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Historically, Nancy Hanks belonged first to the small copper rush of Unaweep Canyon. B. S. Butler of the U.S. Geological Survey visited the district in September 1913 and described the Nancy claim as having two shafts, each reported at more than 100 feet deep, and a tunnel about 300 feet long. A near-surface ore shoot had reportedly been followed to more than 50 feet depth, and J. S. Shaw told Butler that 21 cars of ore averaging 16 percent copper had been shipped from the deposit. That copper chapter is important context, because the specimen-producing fluorite-amethyst material is part of the same narrow, structurally controlled hydrothermal system rather than a broad, rich fluorspar orebody.
Photo: Rob Lavinsky, iRocks.com, via Wikimedia Commons
For collectors, the appeal is visual and local. Colorado has many quartz localities and several fluorite occurrences, but few produce the peculiar Nancy Hanks look: thin cabinet to miniature plates of green fluorite with amethyst druse in violet islands, seams, or blankets, sometimes followed by a later pale green fluorite skin. Good examples have sharp octahedral fluorite faces, strong color contrast, minimal bruising, and enough undulating growth texture to show the sequence of deposition. A specimen may be modest in size yet carry an unusually complete story: copper-era fissures, fluorite prospecting, silicification along a canyon fault system, and a very Colorado combination of green, purple, white, and rusty iron oxides.
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Nancy Hanks Mine is recorded as the Nancy Hanks Mine or Nancy Hanks claim in Nancy Hanks Gulch, Unaweep Canyon, Unaweep mining district, Mesa County, Colorado. Mindat places the locality at 38.85404, -108.55561 and describes it as being in the north half of section 10, T.14S., R.100W., on the north side of Unaweep Canyon, about 12 miles southwest of Whitewater and south of Grand Junction. Nearby names that appear on specimen labels include Nancy Hanks Gulch, Unaweep Canyon, Amethyst Queen claim, Humming Bird Mine, and the broader Unaweep mining district; those are not all interchangeable, although old labels may treat the gulch name loosely.
The deposit is a fissure-vein and mineralized fracture system. In Butler’s 1915 USGS description of the Unaweep copper district, the lower canyon wall in the mine area exposes Precambrian crystalline rocks—granite enclosing schist blocks—overlain unconformably by red shale, red sandstone, and higher gray sandstone. The crystalline rocks are cut by many pegmatite and diabase dikes, many of which strike roughly northwest. Later movement reopened some of these old fissures, and ore fluids deposited calcite, quartz, minor fluorite, pyrite, chalcopyrite, and hematite; near-surface oxidation produced limonite and malachite. At Nancy Hanks specifically, Butler noted that ore occurred in shale a short distance above the granite as well as in the igneous-rock setting, showing how mineralization crossed the old basement-cover boundary.
The fluorspar phase was never the large, clean industrial body that commercial operators prefer. Colorado Geological Survey and USGS summaries describe a few northwest-trending fluorspar veins exposed near Nancy Hanks Bridge along the north side of East Creek, about 13 miles southwest of Whitewater on Colorado Highway 141. These veins were originally sought for precious and base metals and occur as closely spaced mineralized fissures in a Precambrian metamorphic complex. Green fluorite is present with calcite and quartz, but the veins are irregular and discontinuous; additional fluorite occurs along the northwest extension into Wingate Sandstone at the Wooden Door prospect, where sinuous veins average only a few inches thick and were estimated to contain less than 20 percent CaF2. That poor industrial geometry is one reason Nancy Hanks is a specimen locality rather than a major fluorspar mine.
The collector mineralization is more attractive than the ore grades suggest. Mineral-resource work on Mesa County describes colorless to light-green fluorite near the Nancy Hanks mines in northwest-trending faults and fissures in Precambrian and Triassic rocks, occurring in zoned intergrowth with quartz and amethyst. Field and specimen records show the more collectible habit as crusts and plates of green fluorite octahedra, commonly with quartz or amethyst druse, calcite, and locally barite. Some specimens preserve voids or casts where barite or calcite weathered or dissolved out, leaving sculptural negative spaces beneath later quartz or fluorite.
Mining began as part of the late nineteenth- and early twentieth-century Unaweep copper activity. Butler’s 1913 visit found many properties idle, but he documented the Nancy workings as already developed by two shafts and a tunnel, with prior shipments of high-grade copper ore. Subsequent district history includes wartime evaluation of fluorite in the 1940s and fluorspar activity in Nancy Hanks Gulch in the early 1970s, when fluorite was considered for hydrofluoric acid feedstock and steelmaking flux. The small, discontinuous, difficult veins could not support large-tonnage fluorspar production, but they did preserve collectible material in pockets, seams, and crusts.
Specimen history is concentrated in old-stock collections rather than large modern production. EarthWonders records note a group of fluorite and amethyst specimens from Mel Bersch’s collection and state that Bersch once owned the Nancy Hanks claim. Other documented specimens have passed through the Kay Robertson, H. R. McBroom, Allen Dillwith, Dave Bergman, and DanZ Rockshop channels. Dealer and Mindat records show cabinet plates to thumbnails, with examples around 3–13 cm common among illustrated specimens and at least one large old-stock amethyst-on-fluorite plate recorded at 17 cm across. The most desirable pieces are not simply “green fluorite”; they are layered combinations showing Nancy Hanks’ diagnostic paragenesis—green fluorite, purple amethyst, later quartz, calcite or barite relics, and iron-stained matrix from the old copper vein system.
Access today requires caution and current land-status checking. The gulch includes BLM land, patented claims, private property, old workings, and at least one nearby bonded operation, the Humming Bird Mine, operated by Miners Mall, LLC under Colorado permit M-2017-035. State inspection records for the Humming Bird Mine describe a limited-impact hard-rock operation at the entrance of Nancy Hanks Gulch, with boundary markers, signage, safety fencing, and BLM participation in inspections. Those records apply to Humming Bird rather than necessarily to the old Nancy Hanks claim itself, but they illustrate the access problem: this is not a single open public rock pile. Serious collectors should treat all adits, shafts, fenced areas, posted claims, and old dumps as controlled or hazardous unless permission and land status are clear.
Fluorite is the signature Nancy Hanks species, most prized as sea-green to emerald-green translucent octahedra forming thin plates, crusts, and two-sided sheets, commonly associated with quartz, amethyst, calcite, and locally barite. Illustrated specimens show cabinet plates around 12.6 x 7.6 x 2.5 cm, small cabinet examples near 7.7 x 3.5 x 1.3 cm, and numerous miniatures and thumbnails; the best have sharp, glassy octahedral faces, saturated green color, attractive purple fluorescence, and contrasting quartz or amethyst rather than dull massive fluorite. A classic Nancy Hanks paragenesis is two fluorite generations with amethyst between them, or solid green octahedral fluorite coated by purple amethyst and capped by a later pale green fluorite layer; pieces with bruised edges, etched-looking surfaces, or mostly massive green fluorite are much more ordinary.
Amethyst from Nancy Hanks is almost always a combination mineral rather than a stand-alone geode-style quartz specimen: small lilac to purple quartz crystals grow as druse, clusters, seams, or phantom-bearing points on or between green fluorite generations. Documented pieces include thumbnail to cabinet specimens, such as an 88 x 57 x 30 mm fluorite-amethyst specimen recorded on Mindat and a 17 x 7.6 x 3.6 cm old-stock plate listed by M&W Minerals; the finest pieces show lively purple points cleanly perched on green fluorite, with good sparkle, color contrast, and minimal broken tips. Pale, sparse druse is common, but rich purple amethyst distributed in islands across a fluorite plate—or caught in a visible stratigraphic layer between fluorite generations—is what gives Nancy Hanks material its collector identity.
Other documented Nancy Hanks minerals include baryte, calcite, chalcopyrite, hematite, limonite, pyrite, and quartz. No type-locality species are recorded for the mine in the standard locality references; the rarities here are textural and associative rather than exotic species. Baryte is especially worth noting because some fluorite-amethyst specimens show casts or cavities probably left by dissolved or weathered barite, while the copper-era suite—chalcopyrite, pyrite, hematite, limonite, and malachite in the broader district—anchors the decorative fluorite-amethyst specimens to the mine’s original base-metal history.
Nancy Hanks material is distinctive but often loosely labeled. Watch for labels that say only “Nancy Hanks Gulch,” “Unaweep Canyon,” “Mesa County,” “Amethyst Queen,” or “Humming Bird Mine.” Those may refer to nearby but separate occurrences in the same mineralized belt. Conversely, a specimen labeled “Nancy Hanks Mine, Kentucky” is almost certainly mislocated; the collector fluorite-amethyst material discussed here is from Mesa County, Colorado, not the Illinois-Kentucky fluorspar district. For high-end pieces, provenance matters: old labels from Mel Bersch, Kay Robertson, H. R. McBroom, Allen Dillwith, Dave Bergman, or established Colorado dealers add confidence and help separate Nancy Hanks proper from nearby gulch material.
No well-known treatment tradition is associated with Nancy Hanks fluorite-amethyst. The more common issues are condition and labeling. Fluorite has perfect octahedral cleavage, so the exposed green crystal crusts often show bruised tips, rubbed ridges, cleaved corners, or edge damage. Amethyst druse can look intact at a distance while having many tiny broken terminations under magnification. Calcite or barite relics may leave natural casts that resemble damage; examine whether cavities follow crystal outlines and are coated by later quartz or fluorite before assuming they are simply broken areas.
Fluorescence is part of the appeal. Classic Nancy Hanks fluorite has been described as showing excellent purple fluorescence, and dealer records also note blue to blue-purple response under shortwave ultraviolet light. Test gently and avoid heat, acids, or prolonged soaking: these specimens often combine softer, cleavable fluorite with quartz, possible calcite, iron oxides, and porous matrix. If cleaning is needed, use dry mechanical methods first and avoid anything that could attack calcite, loosen old repairs, or change iron staining that is part of the specimen’s character.
Market availability is sporadic. Small pieces appear from time to time from old stock, estate collections, and modern Colorado dealer inventories, but high-quality plates with sharp green octahedra and well-positioned amethyst are not common. The locality is attractive to several overlapping collector groups—Colorado specialists, fluorite collectors, amethyst collectors, and U.S. classic-locality collectors—so strong examples tend to disappear quickly even when prices are still modest compared with famous international fluorite localities.
The old Nancy Hanks story begins as a working miner’s place, not a showy mineral locality. In 1913, Butler rode into a district of steep canyon walls, granite benches, red shale slopes, and idle prospects. The road from Whitewater had heavy grades for the first 8 or 9 miles before settling into Unaweep Canyon. The mine workings were small by western standards—two shafts and a 300-foot tunnel—but the ore was not trivial. The reported Nancy Hanks shipment of 21 cars averaging 16 percent copper explains why the claim mattered in a remote canyon where every ton had to be moved out by wagon.
A colorful Nancy Hanks Gulch oral history preserved by the Humming Bird Mine operators tells of rivalry between the crews on the old workings in the gulch. According to that account, while the Nancy Hanks crew was moving its first three wagon loads of ore down through the neighboring mine area in 1896, a quarrel broke out between the two camps. The neighboring crew was mounting a hoist to a large boulder at the top of a 55-foot vertical shaft; when the miners returned from a night in town, the boulder had been blasted into the shaft, plugging it like a choke stone. The story ends not with a dramatic bonanza but with abandonment: the obstruction reportedly made the working too dangerous and difficult to continue.
The modern rediscovery story belongs to the edge of the same gulch. In fall 2014, Dennis Schneider was prospecting Nancy Hanks Gulch with GPS overlays showing mines, land status, property lines, and geology. He found small amethyst and fluorite pieces, then took a shortcut back toward the parking area through pinyon and juniper. In a clearing he saw amethyst crystals in the dirt, then a metal pipe. That small detour led Dennis and Tammey Schneider to the workings later developed as the Humming Bird Mine, where old portals not shown on maps had to be incorporated into the claim boundary. It is a reminder that Nancy Hanks Gulch is not exhausted in the collector’s sense; it is a structurally mineralized corridor where old copper miners, mid-century fluorite seekers, and modern specimen diggers all saw different value in the same veins.
