adamite from Ojuela Mine, Mexico

Overview

For many collectors, adamite from the Ojuela Mine sets the world standard: vibrant yellow‑green crystal “pinwheels,” shimmering fans and druses on deep red‑brown gossan, and a signature neon‑green fluorescence under short‑wave UV. Beyond the classic yellow‑green, Ojuela produced a remarkable palette including blue‑green cuprian adamite and, famously, a one‑time 1981 pocket of vivid purple manganoan adamite that has never been matched. (mineralogicalrecord.com)

Ojuela is an immense carbonate‑replacement (CRD) system of “chimneys” and “mantos” in reactive carbonate host rocks, oxidized to unusual depths—conditions that favor spectacular secondary arsenates such as adamite, legrandite, and others. The locality’s mineralogical importance and history were documented in a 91‑page Mineralogical Record special issue; the mine, worked since the 16th century and long operated by Peñoles, later became a specimen‑producing classic and a magnet for collectors. (wheretofindrocks.com)

What collectors seek in Ojuela adamite are sharp, lustrous wedge‑shaped crystals grouped in radiating clusters or spheres (“pinwheels”), clean contrast on limonite/goethite gossan, strong UV response, and—in rarer cases—color varieties (blue‑green cuprian; purple manganoan) or color zoning. (mineralauctions.com)

Featured Specimens

Locality Information

Location: Ojuela Mine, Mexico

Search for specimens: View all adamite specimens from Ojuela Mine, Mexico

Ojuela lies near Mapimí, Durango, and is the archetype of a carbonate‑replacement deposit: pipe‑like chimneys and stratabound mantos cut and replace limestones, with oxidation reaching exceptional depths. This geologic architecture and deep supergene alteration produced one of the world’s richest arsenate suites, including adamite. (wheretofindrocks.com)

Mining there dates to Spanish discovery in 1598; the property became a major Peñoles operation in the late 19th–early 20th centuries. Today Ojuela is a tourist site recognized for the restored 1898 Roebling‑designed suspension bridge and guided underground tours; specimen collecting has occurred episodically under permits (notably by Mike New, whose miners uncovered the famous 1981 purple adamite pocket in the San Judas chimney). (en.wikipedia.org)

Characteristics of adamite from Ojuela Mine, Mexico

Crystal habits and colors: The canonical habit is radiating clusters and spherical “pinwheels” of wedge‑terminated orthorhombic crystals, typically yellow‑green to honey‑green. Ojuela also yields blue‑green cuprian adamite and the ultra‑rare purple manganoan variety from the unique early‑1980s pocket. Color zoning (e.g., pink‑magenta cores with green rims) occurs but is uncommon. (mineralauctions.com)
Size ranges: Miniatures and small cabinets are common; radiating fans to 2+ cm and individual crystals to ~1 cm are documented, with occasional larger aggregates on sculptural gossan. (crystalclassics.co.uk)
Associated minerals: Classic associations include calcite, hemimorphite, wulfenite, mimetite, conichalcite, rosasite, scorodite, and fluorite—part of Ojuela’s famed oxidized arsenate suite. (en.wikipedia.org)
Quality factors: Desirable pieces show high luster (“wet” look), sharp terminations, balanced aesthetics on iron‑oxide gossan, and intense green fluorescence (especially under SW‑UV). Blue‑green cuprian and purple manganoan pieces command premiums. (naturesrainbows.com)
Unique features: The 1981 San Judas pocket produced museum‑grade purple adamite now dispersed worldwide; the mine has also produced excellent cuprian crystals and occasional “watermelon‑zoned” clusters. (cambridge.org)

Collector Notes

Fakes/treatments to watch: Beginning in 2020, vividly sky‑blue “hemimorphite” from Ojuela flooded the market; analyses (Raman) identified the dye Phthalocyanine Blue on surfaces—these are artificially colored post‑mining pieces. While not adamite, they are commonly offered alongside Ojuela arsenates; be cautious about provenance and disclosures. (mindat.org)
Stabilization/repairs: Ojuela gossan is often friable; many specimens (from any locale) are legitimately stabilized, repaired, or restored. Reputable dealers disclose such work; expect invisible consolidants on some Ojuela pieces, and avoid aggressive cleaning. (collectorsedge.com)
Condition issues: Radiating adamite clusters chip easily; check for bruising to terminations and for loose “shed” on matrix. Transport and display benefit from rigid bases and clamshell boxes (common for thumbnails).
Rarity/availability and market: Abundant older material exists, but top pieces with large, lustrous fans or unusual colors are scarce. Recent public auction results show common yellow‑green druses and pinwheels selling from sub‑$100 to a few hundred dollars, while exceptional or historically important pieces (cuprian, large fans, purple Mn‑adamite) run into the high hundreds to several thousand dollars; fixed‑price offerings for select miniatures can be $2,500+. (mineralauctions.com)
Quick ID tips: Expect strong green fluorescence under SW‑UV, classic gossan matrix, and wedge‑terminated radiating groups. Treat claimed “bright sky‑blue hemimorphite crystals from Ojuela” with skepticism unless supported by rigorous testing and disclosure. (naturesrainbows.com)

Mineralogical Records & Publications

Thomas P. Moore and Peter K. M. Megaw, “Famous mineral localities: The Ojuela Mine, Mapimí, Durango, Mexico,” The Mineralogical Record, Vol. 34, No. 5 (September–October 2003), pp. 5–91. This Mexico II special issue remains the definitive reference on Ojuela’s history, geology, and minerals; it won the Friends of Mineralogy Best Article award for 2003. (mineralogicalrecord.com)
Robert B. Cook, “Connoisseur’s Choice: Adamite, Ojuela Mine, Mapimí, Durango, Mexico,” Rocks & Minerals, Vol. 74, No. 1 (1999), pp. 40–42. DOI: 10.1080/00357529909602512. A crisp collector‑focused treatment of Ojuela adamite. (mindat.org)
Malcolm Southwood and Peter K. M. Megaw, “Connoisseur’s Choice: Legrandite, Ojuela Mine, Mapimí, Durango, Mexico,” Rocks & Minerals, Vol. 95, No. 4 (2020), pp. 362–371. Provides broader context for Ojuela’s arsenate suite. (mindat.org)
R. Yang et al., “Mikenewite… a new sulfite mineral from the Ojuela mine, Mapimí, Mexico,” Mineralogical Magazine, Vol. 87, No. 4 (August 2023), pp. 534–541. Includes historical notes on Mike New’s permitted specimen mining and the 1981 purple adamite find. (cambridge.org)

Also of interest

Museum and notable collections: The 1981 purple adamites are documented as being dispersed among major museums and private collections (see Yang et al. 2023). (cambridge.org)
Dealer catalogs and auction records: Numerous historical and modern offerings (e.g., Crystal Classics, iRocks/MineralAuctions) illustrate price/quality ranges and classic habits; some listings explicitly reference older 1960s–1980s finds. (crystalclassics.co.uk)

Videos & Media

Why Miners Are Flocking Back to This Abandoned Mine (SciShow, Jan 2, 2025). Short explainer on Ojuela’s second life as a specimen locality; introduces adamite to a general audience. https://www.imdb.com/title/tt35257437/ and syndicated blurb via RealClearScience. (imdb.com)
Adamite (variety manganoan) with Goethite from Ojuela Mine, Mapimí, Mexico (Vimeo clip). Specimen video highlighting the rare purple Mn‑adamite habit. https://vimeo.com/493083679. (vimeo.com)
Adamite with Wulfenite and Mimetite – Ojuela Mine (Catawiki/Barnebys lot video). Short specimen video showing unusual associations from Ojuela with link to Vimeo. https://vimeo.com/1110779945/81cc9ed691. (catawiki.com)
Dealer showcase clips: Several dealers include embedded videos of Ojuela adamite (fluorescence, turn‑table views), e.g., DanZ Rockshop page with “PLEASE SCROLL DOWN FOR VIDEO.” (danzrockshop.com)
About BlueCap Productions: While BlueCap has extensive coverage of mineral shows and Mexican material, no dedicated BlueCap video focused solely on Ojuela adamite was found during this search; their production overview and “What’s Hot” series index are here for reference. (tucsonfineminerals.com)