Adamite

A toxic, uncommon secondary mineral that can be found in oxidised zinc and arsenic-bearing hydrothermal deposits, Adamite is a well-studied material and specimens have been found in Chile, Mexico, USA, France, Germany, UK, Greece, Namibia and Australia although according to Mindat.org, there are 188 localities for this mineral and most of the good specimens are from the Ojuela mine near Mapimi, Chihuahua, Mexico.

Metaphysical Properties:

Adamite is said to: - have healing effects on the physical body

- aid with depression, mental fog, everyday cloudiness and lack of energy

- stimulates the Endocrine System

- aid in everyday chemical imbalances

Identification

Adamite is found in crystals as large as 8cm, can have an intense green or lemon yellow fluorescence under UV light (Short or longwave) and comes in a variety of colours (detailed below) depending on the mineral it contains.

Similar minerals that it may be confused with

Olivenite (image 1 below) - Typically has a greener colour and usually occurs as tall, thin crystals

Smithsonite (image 2 below) - Typically occurs globular and doesn’t fluoresce

Paradamite (image 3 below) - Has a different crystal form

Colours it can be found in

-Colourless

-Yellowish green, various shades of yellow (Contains Iron (Fe))

- Pale green, bluish-green, green (Contains Copper (Cu))

- Rose and violet shades (colour zoned, contains Cobalt (Co))

- Purple (Contains Magnesium (Mn))

Countries it can be found

The Ojuela Mine in Mapimi, Mexico has fine sprays of crystals in Limonite matrix, Tsumeb, Namibia produces sprays that are sometimes purple.

In Laurium, Greece you can find specimens containing copper, turning them blue and green.

Can also be found in USA (California), France (Cap Garonne), Algeria, Chile, Germany, Italy and Turkey.

Scientific Properties

Mohs hardness - 3.5

Formula: Zn2(As)4)OH+Co,Cu

Etymology: Adamite was named after the French mineralogist, Gilbert-Joseph Adam (1795-1881).

Occurrence: Secondary mineral in the oxidized zone of ore deposits

Fracture: Subconchoidal to uneven

Cleavage: Good 1 direction

Crystallography: Orthorhombic, crystals elongated or equant; druses, radial aggregates, and spheroids on matrix

Refractive Index: 1.708-1.773

Birefringence: 0.031-0.050

Luminescence: Intense green in SW (Shortwave), LW (longwave) also lemon yellow in SW

Luminescence type and is it present: Yes, UV-long UV-Short

Pleochroism: Colorless/blue-green/yellow-green. Pale rose/pale rose/ pale purple. Pink/pale rose/colorless

Optics: Biaxial (+/-); 2V=15 degrees (Cu.Var.) to 88 degrees.

Optic Sign: Biaxial+, Biaxial -

Luster: Vitreous

Specific Gravity: 4.32-4.68 (red-violet)

Transparency: Translucent to Transparent

Not sure what these words mean? Click here to see a post explaining them!

Any known fakes?

Synthetics specimens of adamite-olivenite series for spectroscopy research but this is not in the mainstream market.

Can it be faceted?

Although it is found in many places it is very rarely cut into a gem as it is very soft and too fragile, however, collectors do prize its intense fluorescence and will sometimes have it be cut.

Violet crystals (up to 1cm long) would typically yield crystals up to 1-2 carats whilst green crystals (usually not without inclusions) would provide 1-3 carats.

How to care for it

Less than optimal for jewellery use, it is more likely to be found as part of a collection as a specimen rather than as a part of a jewellery collection.

As it is often found in the crumbling Limonite matrix that stains the hands and as such care must be taken when washing Adamite as Limonite is a very crumbly stone when it is scrubbed. Gentle cleaning with a soft-bristled brush or low-pressure air.

Minerals it is often associated with:

- Limonite

- Calcite

- Aurichalcite

- Austinite

- Mimetite

- Wulfenite

- Hemimorphite

Sources

https://www.dakotamatrix.com

https://www.mindat.org

images: google, gemsociety.org