Prince of Wales Island epidote is one of the great American mineral classics: dark, lustrous, sharply terminated, and unmistakably Alaskan in character. The best-known material comes from Green Monster Mountain, with related skarn occurrences in the Copper Mountain–Jumbo district. Collectors prize these specimens for their stout, blocky monoclinic crystals, deep bottle-green to nearly black color, bright vitreous luster, and the striking contrast of white to clear quartz or, more rarely, calcite.
Photo: U.S. Geological Survey
The locality’s mineralogical setting is not an Alpine fissure, even though the finest pieces can compete aesthetically with Alpine epidote. These crystals grew in skarn: limestone and marble host rocks altered by intrusive igneous bodies and mineralizing fluids. The Green Monster Mountain crystal area is part of a broader copper-magnetite-skarn system, where epidote developed with garnet, quartz, diopside, actinolite, magnetite, pyrite, chalcopyrite, and carbonate minerals. That geological environment gives the epidote its robust, compact habit and its dark, iron-rich look.
Historically, the Prince of Wales Island material entered the collector consciousness early. By the first decades of the 20th century, “Sulzer” and “Prince of Wales Island” labels were already appearing on fine epidote specimens, and by the mid-20th century the locality had become an American benchmark. The comparison most often made by older writers and dealers is with the Tyrol—especially Knappenwand—but the Alaskan material has its own personality: broader, heavier crystals; a more rugged skarn aesthetic; and frequent quartz associations, including quartz crystals that can be included by green chlorite and epidote.
Photo: Wikimedia Commons / Rob Lavinsky, iRocks.com
For serious collectors, the most desirable Prince of Wales Island epidotes show sharp terminations, strong luster, deep but not completely dead color, undamaged display faces, and enough translucency at the edges to flash olive or rhubarb-green under a strong light. A superb Green Monster specimen often has a sculptural, almost architectural presence: black-green epidote prisms standing among white quartz, or a single large, twinned crystal with chevron or herringbone surface markings.
Search for specimens: View all epidote specimens from Prince of Wales Island, Alaska, USA
Prince of Wales Island lies in southeastern Alaska, within the old Ketchikan Mining District. Epidote specimens sold simply as “Prince of Wales Island” most often refer to Green Monster Mountain, especially the celebrated epidote crystal locality near the Green Monster copper and magnetite prospects. Older labels may instead read “Sulzer,” “Green Monster Mine,” “Green Monster Mountain,” “Copper Mountain,” or “Jumbo Mine,” reflecting the historic mining geography and the way specimens moved through early collections.
The deposit type is copper-bearing skarn. At Green Monster Mountain, mineralized zones occur in marble near epidotized diorite and related intrusive rocks. The crystal-producing skarn is fractured and fault-controlled, with pockets in garnet-epidote-quartz-uralite-pyrite-chalcopyrite rock. Contemporary geological descriptions emphasize steep faults, skarn mineral growth in fractures, and vugs containing euhedral epidote and quartz in decomposed clayey material. That “pocket in skarn” origin explains why some specimens are nearly floaters, why many have recrystallized or healed surfaces, and why others show contact points where they were extracted from tough pocket walls.
Copper prospecting came first. Green Monster Mountain copper and magnetite showings were discovered in 1900. When C. W. Wright visited in 1908, the workings consisted of two tunnels about 20 meters long and a pit roughly 3 meters deep. Later geological work described massive sulfides in skarn, disseminated sulfides in skarn, and sulfide-bearing veins in skarn and hornfels. The copper showings were never developed into a major producing mine in the way the nearby Jumbo and Copper Mountain operations were, but the skarn pockets made Green Monster Mountain famous among mineral collectors.
The nearby Jumbo Mine and Copper Mountain area are essential to understanding the locality. Jumbo, discovered in 1897 and developed from 1902, produced copper, gold, and silver from skarn ore bodies along the Copper Mountain pluton. Its ore assemblage included pyrrhotite, chalcopyrite, pyrite, sphalerite, molybdenite, epidote, garnet, diopside, quartz, and calcite. The Jumbo epidotes were noted in older geological literature as exceptional, occurring as radiating groups and coarse crystals of complex form lining vugs. Copper Mountain, also discovered in 1897, had high-elevation skarn workings and produced copper-silver-gold ore in the early 1900s; it, too, is associated with epidote-rich skarn and has supplied collectible epidote with quartz.
Collecting access should be treated conservatively. The classic Green Monster epidote locality has been described in Bureau of Mines literature as privately owned, and much of the wider district involves old patented claims, prospects, and lands with mixed ownership. In the 1970s, lessees associated with Eskil Anderson were still exploring the Green Monster crystal pockets. Later specimen records show material collected by or associated with named collectors and leaseholders, but this should not be taken as evidence of open public collecting. Anyone contemplating field work must verify land status, claim status, permissions, and Alaska field-safety requirements before travel.
Production for specimens has been episodic rather than continuous commercial mining. Geological records describe museum-quality epidote crystals being mined by the Smithsonian Institution and other lessees beginning in the 1930s and continuing through at least the period of the 1970s field reports. Collectors also know a major wave of Green Monster material from the Lee Myers era, especially specimens collected between 1969 and 1979. Later pieces from the 2000s and 2010s appear in the collector market, but the bulk of fine material seen today is recycled from older collections rather than freshly mined in quantity.
Notable finds include large, dark, blocky epidote prisms on quartz; doubly terminated epidote crystals; Japan-law twin quartz included or accented by epidote; rare calcite-epidote combinations; and unusual fan-shaped or “jackstraw” aggregates that depart from the more familiar thick Green Monster habit. The locality’s best specimens are large for the species and have long been considered among the finest epidote crystals from North America.
The classic Prince of Wales Island epidote is dark green to greenish black, highly lustrous, and blocky to stout-prismatic. Many crystals are tabular or thickly prismatic rather than slender Alpine needles. In strong light, the darkest faces may open into olive, pistachio, bottle-green, or reddish-rhubarb internal flashes, especially along edges and thinner zones. The best specimens are not merely black; they have depth.
Crystal faces commonly show strong striation. Some Green Monster crystals display conspicuous chevron, herringbone, or fishbone-like markings related to twinning and growth structure. These surface features are part of the locality’s visual signature and are particularly valued when they are sharp, symmetrical, and visible on major display faces. Chisel-shaped, beveled, or complex terminations are common on better pieces; doubly terminated crystals occur and can make superb thumbnails and miniatures.
Habit varies more than casual labels suggest. The textbook Green Monster look is a heavy, blocky crystal or cluster, often with quartz. Other pieces show thinner prismatic crystals in sprays, fan-shaped aggregates, or jackstraw clusters. The unusual fan and jackstraw styles are scarcer and can look superficially like material from other world localities, but verified examples from Green Monster Mountain are known.
Typical specimen sizes range from thumbnails of single 2–3 cm crystals to miniatures and small cabinets with crystals around 1–4 cm. Large, fine crystals over 5 cm are uncommon and desirable; large cabinet pieces with sharp, thick crystals and little damage command special attention. A 6 cm Prince of Wales Island epidote-quartz specimen is represented in USGS educational media, and commercial records document substantial Green Monster cabinet specimens with crystals in the 4–6 cm class.
Quartz is the most important associate for display specimens. It occurs as clear, white, smoky, or slightly greenish crystals, sometimes as fine needles and sometimes as well-formed prismatic crystals large enough to dominate a composition. Quartz crystals may contain epidote or chlorite inclusions, and Green Monster Mountain is well known for Japan-law twin quartz. Calcite is much less common in fine display pieces but creates dramatic white or golden contrast when present. Other documented associated minerals include garnet or grossular, actinolite, diopside, chlorite group minerals, hematite, magnetite, pyrite, pyrrhotite, chalcopyrite, malachite, goethite, clintonite, scapolite, titanite, orthoclase, laumontite, and rare accessory species reported from the skarn system.
Quality is judged by the usual aesthetic factors, but locality-specific priorities matter. A top Prince of Wales Island epidote should have high glassy luster, crisp terminations, strong three-dimensional form, visible green translucency at edges or in transmitted light, and convincing contrast with quartz or calcite. Broad, undamaged display faces are important because dark epidote can otherwise look featureless. Old labels, especially those naming Sulzer, Green Monster Mountain, Copper Mountain, or a major collection provenance, add significant collector interest.
Prince of Wales Island epidote is a mature classic: most fine pieces on the market today are from older collections, not steady modern production. Availability is therefore uneven. Small thumbnails and modest miniatures appear regularly, but sharp, lustrous cabinet specimens with large undamaged crystals are much harder to obtain. Exceptional old Green Monster pieces with strong provenance, major crystal size, quartz contrast, and minimal contacting can sell quickly and at strong prices.
No documented locality-specific fakes or treatments are well established for Prince of Wales Island epidote. The main authenticity issue is attribution. Older specimens may be labeled simply “Sulzer,” “Prince of Wales Island,” “Alaska,” “Green Monster,” or “Copper Mountain,” and those names can refer to related but distinct occurrences. A good label should be preserved, even if the wording is old-fashioned. Conversely, a modern “Green Monster” label on a dark epidote-quartz specimen should still be evaluated by habit, matrix, provenance, and dealer reliability, because epidote from other world localities can be superficially similar.
Repairs and contacts deserve careful inspection. Epidote is hard enough to be durable in the cabinet, but it has cleavage and can chip along terminations and edges. Many genuine Green Monster specimens show contacts where they were removed from pocket walls, and some show natural rehealing or recrystallized break surfaces from growth in a fractured skarn environment. Natural healing is a plus when well developed; glue repairs or rebuilt clusters should be disclosed and priced accordingly.
Condition problems commonly occur on quartz associates before they appear on the epidote. Small quartz crystals may be bruised, chipped, or broken while the epidote remains intact. Dark epidote can also hide edge wear in ordinary lighting, so inspect under a strong, oblique light. A bright face should reflect cleanly; dull patches, frosted edges, and repeated tiny chips reduce value.
Collectors should also watch for misleading visual cues. Dark Green Monster epidote can look almost black in dealer photographs, but under strong light good crystals should show green body color or edge translucency. Pieces described as “nearly black” are not automatically inferior; many classic Alaskan specimens are naturally that dark. What matters is whether the crystal has luster, form, and internal life rather than a flat, opaque appearance.
Green Monster Mountain earned its name in more than one sense. The specimens are beautiful, but the place is not gentle. Geological descriptions place the crystal locality around high, fractured skarn on the mountain, with old adits, pits, snow-covered contacts during late-July mapping, and steep country shaped by intrusive bodies, marble, and faulting. This is the kind of locality where a fine miniature in a drawer represents far more effort than its size suggests.
The early copper men were not looking for cabinet specimens. Green Monster’s showings were discovered in 1900, and by 1908 C. W. Wright found only modest workings: two tunnels, each about 20 meters long, and a pit roughly 3 meters deep. The rock told a more complicated story than the workings did. Sulfides occurred as massive bodies in skarn, as disseminations, and as veins in skarn and hornfels. The ore potential did not create a major mine, but the same fractured, altered system opened the pockets that later made the mountain famous to collectors.
The 1972 geological visit reads like a snapshot of the locality between eras. The authors noted that there had been some stripping where epidote crystals had been mined, but otherwise little appeared to have been done since Wright’s early visit. Lessees of Eskil Anderson were exploring for epidote pockets when the geologists came through. In the skarn, unfractured euhedral epidote and quartz were found “floating” in decomposed pocket mud. Some epidote crystals had cracked and then healed by growths of tiny quartz crystals, preserving in miniature the violent stop-and-start growth history of the mountain.
The locality also has a Smithsonian thread. Mineralogical records note museum-quality epidote mined by the Smithsonian Institution and other lessees beginning in the 1930s, and collector records identify specimens from Arthur Montgomery’s 1937 expedition for the Smithsonian. Those old specimens are especially desirable when they retain institutional or expedition provenance, because they connect a display piece directly to the formative period of American mineral collecting.
Then came the Lee Myers years. Specimens collected between 1969 and 1979 are repeatedly singled out in collector sources, and the best of them remained in Myers’s personal collection. The stories attached to that material are wonderfully specific: epidote crystals with quartz, quartz crystals included with needles of epidote, Japan-law twin quartz from Green Monster, and the playful collector term “epidoteated” for quartz shot through with green needles. These are not generic Alaskan souvenirs; they are specimens from a narrow run of serious collecting at a remote classic locality.
One of the most memorable later specimen descriptions concerns an unusual fan-shaped epidote aggregate from Green Monster Mountain. The collector who supplied it reportedly traveled by helicopter to Green Monster every summer and had only recently found a style of epidote forming in fan-shaped and sometimes jackstraw groups. A few examples were shown in the “American Treasures” display at Tucson, in the Green Monster Mountain case. The specimen itself was described as deep green, highly lustrous, translucent, thin prismatic epidote in a fan-shaped aggregate, finished by a sharp, gemmy, slightly smoky quartz crystal. For a locality known above all for thick, blocky black-green crystals, that find widened the visual vocabulary of Green Monster epidote.
Amethyst
Quartz
Fluorite
Tourmaline
Malachite
Azurite
Rhodochrosite
