Atlantasite (Tasmanite)

Atlantasite, also known as Tasmanite, is a beautiful and relatively rare gemstone that combines two minerals: serpentine and stichtite. Its name originates from the locality where it was first discovered – in the vicinity of the small mining town of Zeehan on the west coast of Tasmania, Australia. The name “Atlantasite” is derived from “Atlas,” the Greek mythological figure, and “site,” which refers to its mineral composition.

The discovery of Atlantasite dates back to the early 20th century, around the 1930s, during mining operations for nickel in the region. Miners initially disregarded it as waste material, but its unique combination of serpentine and stichtite caught the attention of gemstone enthusiasts and collectors.

Serpentine, a common mineral found in many places worldwide, forms the green component of Atlantasite. It is often mottled or veined with purple to pink streaks of stichtite, a rare mineral that gives Atlantasite its distinctive coloration. Stichtite is named after Robert Sticht, who was the manager of the mine where it was first discovered.

Atlantasite’s rarity, combined with its striking coloration and unique patterns, has made it popular among lapidaries and jewelry designers. Its metaphysical properties are also said to promote inner peace, balance, and emotional healing, further adding to its appeal in the realm of alternative healing and spirituality. Today, Atlantasite is not only treasured for its beauty but also appreciated for its historical significance and geological rarity.

Mineral Composition

Atlantasite is composed of two primary minerals: serpentine and stichtite.

1. Serpentine:
   • Serpentine is a group of minerals that are typically green in color and have a waxy to greasy luster.
   • It is composed mainly of magnesium, silicon, and oxygen, with trace amounts of other elements.
   • Serpentine is commonly found in serpentinite rocks, which form through the metamorphism of magnesium-rich rocks like peridotite and pyroxenite.
   • In Atlantasite, serpentine provides the green base coloration and forms the majority of the gemstone’s composition.
2. Stichtite:
   • Stichtite is a rare mineral that belongs to the carbonate group.
   • It is typically found in association with serpentinite rocks and is often formed through the alteration of chromite deposits.
   • Stichtite is renowned for its vivid purple to pink coloration, which contrasts beautifully with the green serpentine in Atlantasite.
   • Chemically, stichtite consists of magnesium, chromium, carbon, and oxygen, with occasional traces of other elements.
   • In Atlantasite, stichtite occurs as veins or patches within the serpentine matrix, adding splashes of color and creating unique patterns.

Together, these two minerals combine to create Atlantasite, exhibiting a harmonious blend of green serpentine and purple to pink stichtite, making it a visually captivating and aesthetically pleasing gemstone.

Formation process and geological occurrences

Atlantasite forms through a geological process involving the alteration of ultramafic rocks, primarily serpentinite, in specific geological settings. Here’s a general overview of the formation process and geological occurrences:

1. Ultramafic Rock Formation: Atlantasite typically originates in ultramafic rock environments, which are characterized by the presence of rocks rich in magnesium and iron, such as peridotite and serpentinite. These rocks often form in the mantle or deep within the Earth’s crust through processes like partial melting and mantle upwelling.
2. Metamorphism and Alteration: The precursor rocks containing serpentine and other minerals undergo metamorphism due to tectonic forces, heat, and pressure. This metamorphic process can occur during events such as regional metamorphism or hydrothermal alteration. During metamorphism, the original minerals within the ultramafic rocks undergo chemical changes, leading to the formation of new minerals like stichtite.
3. Introduction of Stichtite: Stichtite, the purple to pink mineral component of Atlantasite, forms as a secondary mineral through the alteration of primary minerals like chromite in the presence of fluids rich in magnesium and chromium. These fluids may be derived from nearby geological processes or from hydrothermal activity.
4. Vein Formation: As the alteration process progresses, stichtite-rich fluids percolate through fractures and fissures within the host rock. This infiltration leads to the deposition of stichtite within the serpentine matrix, forming veins, pockets, or patches of purple to pink coloration.
5. Geological Occurrences: Atlantasite is primarily found in specific geological settings where ultramafic rocks are present and have undergone alteration. The original discovery of Atlantasite occurred near the town of Zeehan on the west coast of Tasmania, Australia, where serpentinite rocks were mined for nickel. Other occurrences of Atlantasite have been reported in regions with similar geological conditions, such as other parts of Tasmania, as well as in other countries like South Africa and Canada.

Overall, the formation of Atlantasite involves a complex interplay of geological processes, including metamorphism, hydrothermal alteration, and mineral deposition, within ultramafic rock environments. These processes give rise to the unique and visually striking gemstone known as Atlantasite.

Physical and chemical properties

Atlantasite, composed of serpentine and stichtite minerals, possesses a variety of physical and chemical properties that contribute to its uniqueness and appeal as a gemstone. Here are some of its key properties:

1. Color: Atlantasite typically exhibits a base color of green due to the presence of serpentine, with veins, patches, or inclusions of purple to pink stichtite interspersed throughout.
2. Luster: It often displays a waxy to greasy luster, typical of serpentine minerals.
3. Hardness: The hardness of Atlantasite varies depending on the relative proportions of serpentine and stichtite. Serpentine has a Mohs hardness of around 2.5 to 4, while stichtite is softer, with a hardness of about 1.5 to 2.5. As a result, Atlantasite is generally considered to have a hardness within this range.
4. Transparency: Atlantasite is typically translucent to opaque, with varying degrees of transparency depending on the quality and thickness of the material.
5. Crystal System: Both serpentine and stichtite minerals belong to different crystal systems. Serpentine crystallizes in the monoclinic or orthorhombic crystal system, while stichtite crystallizes in the trigonal crystal system. However, in Atlantasite, the individual crystal structures may not always be apparent due to its composition and formation process.
6. Density: The density of Atlantasite varies depending on its composition and the relative proportions of serpentine and stichtite. Generally, it has a density ranging from approximately 2.5 to 3.3 g/cm³.
7. Chemical Composition: Atlantasite is primarily composed of magnesium, silicon, oxygen (from serpentine), chromium, carbon, and oxygen (from stichtite). Trace elements may also be present depending on the specific geological conditions of its formation.
8. Cleavage: Serpentine typically exhibits poor cleavage in one direction, while stichtite may show irregular fracture patterns. These properties contribute to the overall durability and workability of Atlantasite as a gemstone.

Overall, Atlantasite’s combination of contrasting colors, variable hardness, and unique composition make it a fascinating and visually appealing gemstone with distinctive physical and chemical properties.

Uses and Applications

Atlantasite, with its unique coloration and metaphysical properties, finds various uses and applications:

1. Jewelry: One of the primary uses of Atlantasite is in jewelry making. Its attractive combination of green serpentine and purple to pink stichtite makes it a popular choice for gemstone enthusiasts and designers. Atlantasite is often fashioned into cabochons, beads, pendants, and other ornamental pieces for use in earrings, necklaces, bracelets, and rings.
2. Metaphysical and Spiritual Practices: Atlantasite is believed to possess metaphysical properties that promote inner peace, emotional healing, and balance. It is often used in alternative healing practices, meditation, and energy work. Some people use Atlantasite as a tool for chakra alignment, stress relief, and enhancing spiritual growth and intuition.
3. Collectibles and Decorative Items: Due to its rarity and aesthetic appeal, Atlantasite specimens are sought after by mineral collectors and enthusiasts. Small polished pieces or rough specimens may be collected and displayed for their natural beauty and geological significance.
4. Lapidary Arts: Lapidaries and gemstone artisans may work with Atlantasite to create custom gemstone carvings, sculptures, and objets d’art. Its unique color patterns and variable hardness allow for creative expression in lapidary arts.
5. Gifts and Souvenirs: Atlantasite jewelry and decorative items make for meaningful and unique gifts, particularly for individuals interested in gemstones, metaphysics, or the natural beauty of Tasmania, where it was first discovered.
6. Alternative Healing Practices: Some practitioners incorporate Atlantasite into holistic healing modalities such as crystal healing, reiki, and aromatherapy. It may be used in crystal grids, placed on the body during energy sessions, or worn as jewelry to facilitate healing and spiritual growth.
7. Historical and Geological Education: Atlantasite’s discovery and geological significance contribute to its educational value. It serves as a tangible example of geological processes such as metamorphism and mineral formation, providing insight into the Earth’s dynamic history.

Overall, Atlantasite’s versatility, beauty, and perceived metaphysical properties make it a valued gemstone in various industries and practices, ranging from jewelry making to alternative healing and beyond.

Localities

Atlantasite is primarily found in specific geological settings where serpentinite rocks have undergone alteration, leading to the formation of stichtite-rich veins or pockets within the serpentine matrix. Here are some notable localities where Atlantasite has been discovered:

1. Zeehan, Tasmania, Australia: The original discovery of Atlantasite occurred near the town of Zeehan on the west coast of Tasmania. This region is renowned for its rich deposits of serpentinite, where Atlantasite was first identified in association with nickel mining operations.
2. Stichtite Hill, Tasmania, Australia: Stichtite Hill, located near the town of Dundas in Tasmania, is another significant locality for Atlantasite. It is named after the stichtite mineral, which is a prominent component of Atlantasite found in this area.
3. Barberton, Mpumalanga, South Africa: Atlantasite has also been reported from the Barberton greenstone belt in Mpumalanga province, South Africa. This region is known for its diverse mineral deposits and geological formations, including serpentinite occurrences where Atlantasite can be found.
4. Various Locations in Canada: Atlantasite has been reported from several locations in Canada, including Newfoundland and Labrador, where serpentinite rocks are present. Although not as well-known as its occurrences in Australia, Atlantasite from Canadian localities exhibits similar geological characteristics.
5. Other Occurrences Worldwide: While Atlantasite is most commonly associated with Australia and South Africa, it may also occur in other regions where suitable geological conditions exist, such as regions with serpentinite deposits and evidence of hydrothermal alteration.

These localities represent some of the notable sources of Atlantasite, where specimens have been collected for various purposes, including gemstone jewelry, mineral specimen collections, and geological research.