14.01 ct AGRELLITE – CANADA

Agrellite

Agrellite is a gemstone that embodies the stark, clinical beauty of the rare-earth alkaline environments. A sodium calcium silicate, it is a mineral I have always found fascinating for its “ghostly” aesthetic; it typically occurs as elongated, lath-like crystals or massive, fibrous aggregates that range from a pure, “star-white” to a delicate, pale grey or greenish tint. It is a stone of the high-alkali pegmatites and complex metamorphic systems, representing a specific chemical niche where sodium and calcium dominate the silicate framework. For the specialist, Agrellite is a prize of structural rarity and phenomenal response—it possesses a pearly luster that makes it look like petrified silk, but its most dramatic secret is revealed only when the room goes dark and the ultraviolet light is switched on.

The Heritage & Discovery

Historical Significance: Agrellite is a vital species for understanding the mineralogy of “agpaitic” environments—rare, silica-undersaturated igneous rocks. Historically, it was a significant discovery because it expanded our knowledge of the sodium-calcium silicates in complex lithium and rare-earth deposits. In the world of fine minerals, it is celebrated for its incredible fluorescence, standing as a favorite for those who build “light and shadow” collections. It stands as a symbol of the hidden complexity of white minerals, bridging the gap between common rock-formers and the elite world of rare, light-reactive species found in the far north.

Discovery: The mineral was first described in 1976 and was named in honor of Stuart Olaf Agrell (1913–1996), a distinguished mineralogist at the University of Cambridge who was a leading authority on the minerals of metamorphic and alkaline rocks. The type-locality is the Kipawa Complex in Quebec, Canada. Naming this resilient and geometrically sharp species after him was a fitting tribute to his exhaustive work in mineral identification. Since its formal identification, it has become the definitive representative of its group for collectors of Canadian rarities.

Important Mines: The undisputed world capital for Agrellite is the Kipawa Alkaline Complex in Quebec, Canada. This site has produced the most well-defined and large-scale specimens ever recorded. I also have a high regard for the material coming from the Khibiny Massif on the Kola Peninsula, Russia. For the vault, I prioritize the Kipawa material for its historical pedigree and its legendary UV response, which remains the global benchmark for the species.

Mineralogical Profile

Description: Agrellite is a sodium calcium silicate fluoride that crystallizes in the triclinic system. It sits at a 5.5 on the Mohs scale, making it a relatively durable mineral, though its fibrous or “lath-like” habit means it can be prone to splintering if struck along its length. It is characterized by its pearly to vitreous luster and its stark, clean white appearance.

One of its most identifying traits is its vivid fluorescence. Under short-wave ultraviolet light, Agrellite erupts into an intense, “bubblegum” pink or magenta glow, which provides a startling contrast to its daylight-white color. It has a moderate refractive index (approx 1.57 to 1.58) and a characteristic “silky” texture on broken surfaces. Because it is a sodium-rich silicate, it is often found in intimate association with other rare species like Eudialyte or Miserite. When I select a piece for the collection, I look for “fresh” laths with a high-gloss pearly sheen, as these represent the species in its most perfect and reactive form. It is a light, sophisticated mineral that offers a window into the rare chemistry of the planet’s alkaline deep.

Chemical Formula: NaCa₂Si₄O₁₀F