Overview

Adamite is a zinc arsenate [Zn2(AsO4)(OH)] beloved by collectors for its luminous colors and vivid fluorescence. Most classic pieces show sharp wedge-shaped crystals and radiating sprays on rusty-brown limonite/goethite matrix, often with delicate drusy coatings that sparkle even in soft light. The species ranges from colorless to lemon-yellow, with prized varieties colored by trace elements: copper-bearing “cuprian” adamite can be mint to rich emerald green, and cobalt-bearing “cobaltoan” adamite ranges pink to purple. Under shortwave UV, many adamites blaze an intense yellow-green. Aesthetic associations with smithsonite, hemimorphite, mimetite, wulfenite, aurichalcite, calcite, and other oxidized-zone minerals create some of the most eye-catching combination specimens in the hobby.

Crystals are usually small—often millimeter to centimeter scale—but they can form hemispherical “balls,” fan-like aggregates, or drusy carpets that give great visual impact. The finest examples, especially from Ojuela (Mexico), Tsumeb (Namibia), Lavrion (Greece), and the 79 Mine (Arizona), are highly collectible and display beautifully in both daylight and UV-lit cases.

Popularity

Adamite has been a collector favorite since the 19th century, admired for its color range, diversity of habits, and uniquely bright fluorescence. The species sits at a sweet spot of accessibility and excitement: attractive small specimens are attainable for new collectors, while top-end classics from Ojuela and Tsumeb command strong prices. The type locality of Lavrion provides historical significance, and the 79 Mine offers modern, vividly green cuprian druses that glow under UV. Because adamite often occurs in richly mineralized oxidative environments, it appears in striking combinations—lemon-yellow sprays on iron oxide, green fans amid white calcite, or green-on-brown contrasts that read beautifully even from across a room. With every pocket showing new habits, textures, and color nuances, adamite retains enduring appeal across all collecting levels.

Top Collecting Localities

Ojuela Mine, Mexico

The Ojuela Mine (Mapimí, Durango) is the most famous source of adamite, producing a spectacular array of habits and colors for more than a century. Classic pieces feature lemon-yellow to colorless crystals in radiating fans, hemispherical “balls,” and sparkling druses on iron-oxide gossan. Cuprian adamite from Ojuela ranges from pastel apple-green to saturated emerald, while rarer cobaltoan pieces show delicate pink to purple hues. Specimens frequently occur with calcite, hemimorphite, mimetite, aurichalcite, rosasite, and smithsonite, making for wonderful contrasts and combinations. Many Ojuela specimens display powerful yellow-green fluorescence under shortwave UV, a signature that further elevates their display appeal. Large, undamaged hemispheres and well-balanced matrix pieces with fresh luster are especially coveted.

Lavrion Mining District, Greece

Lavrion (Attica) is adamite’s type locality and remains a classic source. Here, adamite often forms as drusy coatings, spherical aggregates, and delicate radiating groups on iron-oxide matrix. Trace copper frequently imparts appealing mint to apple-green tones; pure zinc-dominant material tends toward colorless to lemon-yellow. While individual crystals can be small, the aesthetic comes from the contrast of bright druse against brown gossan, sometimes accompanied by calcite, smithsonite, and other copper arsenates. Lavrion adamite is famously fluorescent—its intense yellow-green response under SW UV makes even small pieces pop in a UV-lit cabinet. Fine, complete hemispheres and even, richly covered druses are especially desirable to locality collectors and fluorescence enthusiasts alike.

Tsumeb Mine, Namibia

Tsumeb produced some of the most refined, sharply crystallized green “cuprian” adamites known. These can be richer in copper than many other localities, yielding saturated bottle-green to yellow-green hues with excellent luster on dolomite or limonite. Crystals can be prismatic, blocky, or form radiating groups with superb definition, often associated with smithsonite, mimetite, and other Tsumeb classics. Note that some green material historically labeled “cuprian adamite” from Tsumeb (and elsewhere) may actually be zincolivenite under modern nomenclature; regardless, the aesthetics are outstanding. Tsumeb green adamites are prized for their clarity, color saturation, and crisp crystal form—and they also tend to fluoresce, though responses vary with chemistry.

Collector’s Guide

Evaluating Specimen Quality

• Color and Variety: Color is a primary driver of value in adamite. Bright lemon-yellow is classic; saturated apple- to emerald-green cuprian pieces are highly sought after; and rarer cobaltoan (pink to purple) examples command strong interest. Deep, even color that shows well in ambient light is ideal. Note that green “cuprian adamite” from some localities may be zincolivenite; both are desirable, but accurate labeling matters.

• Fluorescence: Strong yellow-green fluorescence under shortwave UV is a hallmark of the species, adding a second dimension of display. Green, copper-rich material may fluoresce less intensely than yellow zinc-dominant pieces, but many still show an attractive response. A specimen that looks great both in daylight and under UV holds broad appeal.

• Crystal Form and Habit: Adamite’s beauty often lies in radiating sprays, hemispherical aggregates, and drusy carpets. Look for sharp, lustrous crystal faces and well-defined radial structure within spheres. Even, complete hemispheres and elegant fans are highly aesthetic. Single larger crystals exist but are rare; when present, crisp terminations and glossy luster are key.

• Aesthetics and Composition: The contrast of bright adamite on dark limonite/goethite matrix is a classic. Composition matters: balanced, three-dimensional architecture; pleasing crystal placement; and complementary associations (e.g., adamite with calcite or smithsonite) enhance value. For drusy pieces, even, continuous coverage without bald spots is a plus.

• Size and Impact: Because adamite crystals are typically small, overall visual impact outweighs sheer size. A modest cabinet specimen with electric color, strong luster, and good composition can outshine a larger but dull piece. Spherical aggregates over a few centimeters that are intact and well-placed are scarce and desirable.

• Condition: Adamite is brittle (Mohs ~3.5) and grows on crumbly oxide matrices. Inspect drusy surfaces and hemispheres for bruising or flattened areas. Check for stabilization or repairs around the matrix–crystal interface. Minor, non-distracting matrix rubs are common; pristine, undamaged hemispheres or fans command premiums.

Detecting Repairs or Treatments

• Reattachments and Stabilization: Because gossan matrix is friable, crystals or hemispheres are sometimes reattached or stabilized with clear epoxy. Under magnification, look for glossy glue lines along the base of hemispheres or a subtle “meniscus” at the matrix contact. Longwave UV can reveal fluorescing adhesive in some cases.

• Composite or “Assembled” Pieces: Be cautious of crystals or hemispheres mounted onto unrelated matrix to create more dramatic compositions. Check that associated minerals and matrix textures match known paragenesis for the locality.

• Polishing and Surface Work: Polishing is uncommon for adamite but not impossible—an unnaturally smooth or glassy surface on what should be a drusy hemisphere is a red flag.

• Label Accuracy (Cuprian vs. Zincolivenite): Copper-bearing green material labeled “cuprian adamite” may, under modern classification, be zincolivenite. Visual separation is not reliable; if species identity is critical, seek analytical confirmation. This is more a labeling issue than a “treatment,” but it affects value for species-purist collections.

Care and Storage

Adamite is a relatively soft, brittle arsenate—handle with care.

• Handling and Display:

  • Hardness ~3.5; avoid touching drusy surfaces and hemispherical aggregates.
  • Support matrix pieces from beneath with two hands; use museum putty or a tailored stand to prevent shifting.
  • Adamite shows strong SW UV fluorescence—safe to enjoy, but avoid prolonged high-heat exposure from UV lamps.

• Cleaning:

  • Best: gentle dusting with a soft brush or air bulb.
  • If needed, a quick rinse in distilled water with a drop of mild soap; pat dry. Do not soak for long periods—oxide matrices can weaken.
  • Avoid acids, strong chemicals, and ultrasonic cleaners; these can damage both adamite and matrix and may leach arsenates.

• Environment:

  • Keep away from heat sources and extreme temperature changes to prevent cracking or matrix shedding.
  • Normal room lighting is fine; colors are generally stable. LEDs are ideal for display (low UV, low heat).
  • Because adamite contains arsenic, practice good hygiene: avoid inhaling dust, don’t lick or handle while eating, and wash hands after handling or cleaning.

• Storage:

  • Store individually in padded boxes or compartments so harder specimens don’t abrade the adamite.
  • For drusy or ball-like aggregates, avoid pressure on the surface; support by the matrix.
  • Label with full locality and, for green pieces, note if “cuprian”/possible zincolivenite; provenance enhances value.

By focusing on color, luster, form, fluorescence, and sound matrix integrity—and by handling with care—you can build an adamite suite that displays brilliantly in both daylight and UV, representing one of the most charismatic minerals from the oxidized zones of classic mines worldwide.