3.70 ct BARRERITE – USA

Barrerite represents the "arctic purity" of the zeolite world. A rare sodium aluminum silicate, it is a species I discovered during my time in Tucson, having never previously heard of this remarkable Alaskan material. It typically presents as beautiful, "white goose-colored" crystals with a pearly to vitreous luster. For the specialist, Barrerite is a prize of structural rarity; it is the third orthorhombic polymorph of the Heulandite-Stilbite group, a distinction that makes it a "holy grail" for the systematic collector. It is a stone of "accidental discovery," offering a sophisticated, "snow-white" brilliance that makes it a true "frontier gem" for the systematic vault.

Historical Significance: Barrerite is a vital species for understanding the low-temperature hydrothermal alteration of volcanic rocks in coastal environments. Historically, it remained hidden within the rugged cliffs of Alaska until its formal identification in the 1970s. In the world of fine minerals, it is celebrated for the fascinating narrative of its discovery. As the story goes, the material was first found by a man who was chasing a goose that had run out into the ocean during low tide. Upon finally catching the goose, he spotted a white crystal in the mud and took it home to show a gemologist—and the rest is history. While I cannot verify the truth of the "goose chase," I can personally guarantee the rarity of this gem. It stands as a symbol of serendipity, bridging the gap between a hunter's luck and the elite world of mineralogical science.

Discovery: The mineral was formally named in 1974 in honor of Richard Maling Barrer, a New Zealand-born chemist and pioneer in zeolite research. Scientifically, it is a sodium-dominant zeolite. Its discovery at Rocky Bay provided mineralogists with the first clear look at this specific orthorhombic lattice, helping to complete the map of the Stilbite-Heulandite-Barrerite series. My own respect for this material grew from its "pure" aesthetic; the contrast between the snow-white crystals and the dark volcanic matrix captures the stark, beautiful spirit of the Alaskan coastline where it was birthed.

Important Mines: The undisputed world capital and type-locality for this rare gem is Rocky Bay on Kuiu Island, in the Alexander Archipelago, Alaska, USA. This remains the definitive source for the "goose-white" crystals that set the global benchmark. I also have a high regard for the rare occurrences found in Sardinia, Italy, and Norway. For the vault, I prioritize the Alaskan material for its unmatched historical narrative and its association with the "frontier" mineralogy of the Pacific Northwest.

Description: Barrerite is a sodium aluminum silicate that crystallizes in the orthorhombic system. It sits at a 3 to 4 on the Mohs scale, making it a soft and delicate mineral that must be handled with extreme care to avoid bruising its thin, tabular faces. It is characterized by its pearly luster—particularly on the cleavage planes—and its unmistakable "bone-white" to colorless transparency.

One of its most identifying traits is its perfect cleavage ({010}) and its specific gravity ($SG \approx 2.13$), which makes it feel surprisingly light and delicate in the hand. It has a low refractive index ($n \approx 1.47$ to 1.48) and a characteristic tabular habit, often appearing as "stacked" or "leaf-like" crystals. Because it is a zeolite, it is often found in association with Quartz, Calcite, and other members of the Heulandite group. When I select a piece for the collection, I look for "sharp" tabular outlines and a "frosted-white" saturation, as these highlight the sophisticated, three-dimensional geometry of the mineral's growth. It is a light, high-vibration mineral that offers a unique, "arctic" beauty unlike any other zeolite species.

Chemical Formula: Na₂(Al₂Si₇O₁₈)·6H₂O