0.75 ct ANTHRACITE – USA

Anthracite

Anthracite represents the “carbon soul” of the mineral world. While most identify coal as a mere industrial fuel, I have always respected this specific variety for its transition into a legitimate, “jet-black” gemstone. As you correctly noted, this is likely one of the few faceted coal gems in existence, making it an essential addition to a truly “insane” and comprehensive collection. For the specialist, Anthracite is a prize of metamorphic purity; it is the highest grade of coal, having endured the most intense pressure and heat. It offers a sub-metallic, “gunmetal” luster that, when faceted, provides a sophisticated, “dark-mirror” brilliance that challenges the aesthetics of even the finest Black Spinel or Jet. It is a stone of “condensed power,” providing a deep, grounding aesthetic for the systematic vault.

The Heritage & Discovery

Historical Significance: Anthracite is a vital link in the Earth’s carbon cycle, representing the final stage of coalification. Historically, it was the “black gold” of the Industrial Revolution, prized for its smokeless burn. In the world of fine minerals, it is celebrated for its natural hardness and density compared to softer coals like Bituminous or Lignite. It stands as a symbol of endurance and transformation, bridging the gap between ancient organic matter and the elite world of “faceted rarities.” It serves as a reminder that with enough pressure and time, even the most “industrial” of materials can achieve a crystalline elegance that demands a place in a high-end gemstone vault.

Discovery: The name is derived from the Greek anthrakites, meaning “coal-like.” While coal has been used since antiquity, the recognition of Anthracite as a distinct, high-metamorphic variety occurred in the late 18th century. Scientifically, it is a non-crystalline, carbon-dense organic material. Its “discovery” as a gem-grade material is credited to lapidaries who recognized that its high carbon content (often over 90%) allowed it to take a high-gloss, metallic polish without the “sooty” residue of lesser coals. My own respect for this material grew from its “ink-black” depth; unlike Jet, which is a precursor, Anthracite has a more “metallic” feel and a sharper light return when faceted.

Important Mines: The undisputed world capital for the finest, most compact Anthracite is the Coal Region of Northeastern Pennsylvania, USA (the “Anthracite Capital of the World”). I also have a high regard for the high-quality deposits in South Wales, United Kingdom, and the Donbas region of Ukraine. For the vault, I prioritize the Pennsylvania material for its exceptional structural integrity, which allows it to withstand the rigors of the faceting wheel.

Mineralogical Profile

Description: Anthracite is an organic, non-crystalline (amorphous) mineraloid. It sits at a 2.5 to 3 on the Mohs scale, making it a soft gem—similar to Amber or Jet—that requires a delicate touch and a protective setting. It is characterized by its sub-metallic to vitreous luster and its absolute, light-absorbing “void-black” color.

One of its most identifying traits is its conchoidal fracture and its surprisingly light weight ($SG \approx 1.3$ to 1.8). Because it is composed almost entirely of carbon, it has a “warm” feel to the touch, unlike “cold” stones like Onyx. It has a high refractive index for an organic material, which contributes to its “shimmering” surface when cut into geometric outlines. Because it is a product of regional metamorphism of peat and plant matter, it is often found in association with Shales and Sandstones. When I select a piece for the collection, I look for a “flawless” polish and the absence of pyrite “flecks,” as these highlight the sophisticated, monochromatic geometry that makes faceted Anthracite a standout for the specialist. It is a dense, grounding material that offers a unique, “industrial-chic” beauty unlike any other organic gem.

Chemical Formula: C (approx. 92–98% Carbon)