Stibnite in Alaska: Antimony’s Shimmering Legacy in the Last Frontier
Locations and mineral Properties
Stibnite (Sb₂S₃), the lustrous, silvery-gray antimony sulfide mineral, may not be a household name, but it has a rich and often explosive history, particularly in Alaska, where its gleaming crystal blades once played an unsung role in wartime industry and gold exploration. Stibnite forms in low-temperature hydrothermal environments, typically alongside quartz, gold, galena, cinnabar, and barite. Its elongated, orthorhombic crystals are soft (just a 2 on the Mohs scale), metallic, and striking in appearance, often tarnishing to iridescent blues and violets that catch the eye of collectors. Despite its beauty, it’s extremely brittle, prone to breaking at the lightest touch, and somewhat toxic due to its antimony content. Nonetheless, it was used for centuries as a cosmetic pigment in powdered form, particularly by the ancient Egyptians as kohl eyeliner, and as a medicine and alchemical curiosity in medieval Europe. Alaska’s relationship with Stibnite is tied tightly to its gold mining history and its brief but critical wartime importance. The mineral occurs in scattered deposits across the state, including the Fairbanks mining district, especially Gilmore Dome and the Circle District, where it appears in gold-quartz veins. Other known stibnite zones include the Kuskokwim Mountains, the Alaska Peninsula, and Slate Creek near Wiseman in the Brooks Range. It was the latter that became particularly important during World War II, when global supply chains for antimony (then dominated by China and Bolivia) were disrupted. The U.S. government, desperate for domestic sources, subsidized mining in remote locations like Alaska. Stibnite was smelted into antimony, a strategic metal vital for hardening lead used in bullets and battery plates, and for producing flame-retardant materials used in everything from uniforms and tents to electrical wiring. While mining operations in Alaska were short-lived, they made a significant contribution to the war effort and left behind a legacy of mineral prospects, some of which remain accessible to rockhounds today. Today, stibnite’s primary use remains in the production of flame retardants and alloys, but it’s also important in the electronics and plastics industries. It continues to be used in safety equipment, glass, pigments, and even some forms of semiconductor research. The mineral’s delicate, spear-like crystals, especially when radiating in fan shapes or sprays, make it a favorite among collectors, though intact Alaskan specimens are rare due to the harsh freeze-thaw cycles and difficulty of extraction in remote terrain. Interestingly, stibnite is also used as an indicator mineral in geochemical surveys; its presence can hint at nearby gold or mercury deposits, making it doubly valuable in the field. And while most Alaskans may not know it, this mineral played a small but fiery part in the story of America’s industrial and military rise. Whether seen glinting in a quartz vein in the Interior, or quietly weathering in a forgotten Brooks Range prospect, stibnite is a reminder that even the most delicate minerals can leave a sharp mark on history.
Key Locations in Alaska –
Wiseman area, Brooks Range
Coordinates: ~ 67°29'19"N 150°12'27"W
This is one of Alaska’s most historically significant stibnite occurrences. During World War II, Slate Creek was mined for antimony to support the U.S. war effort. The mineral occurs in quartz-carbonate veins associated with gold and arsenopyrite. Access today is remote, usually via small aircraft to Wiseman or Coldfoot, followed by overland travel. The surrounding country is rugged but beautiful, with stibnite occurring in both float and outcrop. This area lies within general state lands, but always verify land status (some claims may still exist) before collecting.
Gilmore Dome (Fairbanks Mining District)
Coordinates: ~ 64°57'50"N 147°22'17"W
Located northeast of Fairbanks, Gilmore Dome hosts multiple gold-quartz veins that historically produced small quantities of stibnite. While it’s mostly known for gold, antimony occurs as a minor ore and gangue mineral. This area is partially accessible by road via the Steese Highway and trail systems near Fox and Cleary Summit. Some ground here is privately held or claimed, so consult state records or contact the Alaska Division of Geological & Geophysical Surveys before collecting. Float stibnite crystals have been reported in historical placer tailings.
Circle District
Coordinates: ~ 65°36'18"N 144°49'18"W
Another Interior district with known stibnite occurrences, the Circle District includes quartz-sulfide veins where stibnite is a minor component. Historically mined for gold and silver, these sites often show complex sulfide assemblages including galena, sphalerite, arsenopyrite, and stibnite. Central is accessible by road (Steese Highway), and some nearby prospects may be reachable via maintained or rough ATV trails. Always research land status and watch for posted mining claims.
Stepovak Bay Area (Alaska Peninsula)
Coordinates: ~ 55°50'04"N 159°57'55"W
The Stepovak Bay mercury belt includes stibnite associated with cinnabar in altered volcanic rocks. Though very remote and accessible only by boat or floatplane, this region was prospected historically and holds interest for collectors of both mercury and antimony minerals. Due to the presence of mercury, proper precautions and protective equipment are advised, and some areas may be off-limits for environmental reasons.
Lower Yukon-Kuskokwim Region
Coordinates: ~ 62°04'27"N 162°30'26"W
This remote western district saw some stibnite occurrence associated with gold-bearing quartz veins. Access is extremely limited, usually by bush plane or river travel, but exploratory reports from the mid-1900s documented stibnite in altered schists and associated hydrothermal zones. Most of the region is undeveloped wilderness and often within Native Corporation or federal lands, check BLM and Alaska Native land status before attempting to collect.
Important Rockhounding Notes:
Stibnite is soft, brittle, and slightly toxic. Always handle specimens carefully and wash your hands after contact. Avoid inhaling dust or breaking crystals unnecessarily.
Many stibnite locations are on state or federal land, and some are under active or historical mining claims. Verify land status using the Alaska Mapper (DNR) or contact the Bureau of Land Management.
Respect subsistence and Native Corporation lands, trespassing or unauthorized collecting is prohibited.
While stibnite is not radioactive, it is often found with minerals like arsenopyrite or cinnabar. Exercise caution and store your samples safely.
A side not from the author - I personally am currently being affected by exploration of antimony ores such as stibnite, I acknowledge the need for mining and exploration but am going implore our politicians for more transparency and more restrictions on mining. My residential neighborhood should not have to share our road and water supply with a mining corporation. My taxes pay for the upkeep of these roads and last time I checked, these corporations paid much less in taxes than the combined taxes of residents in the affected area, we should have more of a say.