0.90 ct INDICOLITE TOURMALINE – BRAZIL

Indicolite

Indicolite represents the “oceanic depth” of the tourmaline group. An elbaite species defined by its specific coloration, it is a mineral I have always respected for its rare, “neon-indigo” to “teal-blue” hues—a color profile that is exceptionally difficult to find in the mineral kingdom without the presence of iron or copper. The name is derived from the Latin indicum, referring to the indigo plant. For the specialist, Indicolite is a prize of chromatic sophistication; it offers a range from a deep, “midnight” navy to a bright, “electric” lagoon blue. It is a stone of “fluid clarity,” providing a high-saturation, high-frequency aesthetic that makes it a true “crown jewel” for the systematic vault.

The Heritage & Discovery

Historical Significance: Indicolite has been a favorite of royalty and connoisseurs for centuries, though it was often misidentified as Sapphire in ancient times. Historically, it was part of the “gem rainbow” discovered in the legendary pegmatites of Europe and Brazil. In the world of fine minerals, it is celebrated for its complex pleochroism; when viewed from different angles, the stone can shift from a vivid blue to a deep, “inky” green. It stands as a symbol of tranquility and mental clarity, bridging the gap between common silicates and the elite world of “Paraiba-adjacent” precious gems. It serves as a reminder that nature can produce a blue so pure it challenges the dominance of the corundum family.

Discovery: As a variety of Elbaite, its history is tied to the broader discovery of Tourmaline in the 18th and 19th centuries. Scientifically, it is a complex sodium lithium aluminum borosilicate. Its “discovery” as a specific variety occurred as mineralogists began to map how trace amounts of iron ($Fe^{2+}$) influence the light absorption within the tourmaline lattice to create blue. My own respect for this material grew from observing its extraordinary “open” color in the finest Afghan and Brazilian specimens, where the blue remains vibrant even in low light, avoiding the “black-out” effect common in iron-heavy stones.

Important Mines: The undisputed world capital for the finest “electric” Indicolite is Minas Gerais, Brazil, specifically the Pederneira and Cruzeiro mines. I also have a high regard for the spectacular, “water-clear” lagoon blues from the Nuristan Province in Afghanistan and the “teal” treasures from Namibia. For the vault, I prioritize the Brazilian material for its unmatched crystal size and the Afghan stones for their superior “neon” transparency.

Mineralogical Profile

Description: Indicolite is a member of the Elbaite (Tourmaline) group that crystallizes in the trigonal system. It sits at a 7 to 7.5 on the Mohs scale, making it an exceptionally durable and hard gemstone suitable for the finest jewelry. It is characterized by its vitreous luster and its unmistakable palette of blue, teal, and indigo.

One of its most identifying traits is its strong pleochroism and its vertical striations along the crystal faces. It has a moderate refractive index ($n \approx 1.62$ to 1.64) and a specific gravity ($SG \approx 3.0$ to 3.1). Because it is a pegmatite mineral, it is often found in association with Lepidolite, Cleavelandite, and Smoky Quartz. When I select a piece for the collection, I look for “even” color distribution and the absence of “closed” c-axis (dark ends), as these highlight the sophisticated, three-dimensional geometry that makes Indicolite a standout for the systematic specialist. It is a dense, high-vibration mineral that offers a unique, “aqueous” beauty unlike any other tourmaline variety.

Chemical Formula: Na(Li,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄