6.70 ct STILBITE – INDIA

Stilbite Stilbite is a mineral that possesses a unique, soft elegance that sets it apart from the sharper, more aggressive crystal forms. A prominent member of the Zeolite group, it is famous for its "bow-tie" or "sheaf-like" aggregates that look like they’ve been bundled together by hand. I have always been moved by its pearly luster—it has a gentle, shimmering glow that reminds me of silk. In the world of mineral collecting, Stilbite is often the perfect aesthetic companion, frequently found perched atop dark volcanic rock or alongside sparkling green Apophyllite. It is a stone that represents the quiet, beautiful crystallization that happens within the gas bubbles of ancient lava flows. The Heritage & Discovery Historical Significance: Stilbite has played a major role in the study of zeolites—minerals known for their "molecular sieve" properties, which allow them to trap and exchange ions. Historically, it was one of the first minerals where scientists observed the phenomenon of "swelling" when heated, a characteristic that defines the entire zeolite family. It stands as a classic example of secondary mineralization in basaltic cavities, providing geologists with a clear record of the low-temperature hydrothermal fluids that once pulsed through volcanic ranges. Discovery: The mineral was first distinguished as a unique species in 1797 by René Just Haüy. The name is derived from the Greek word stilbe, meaning "luster" or "to shine," which is a direct reference to the beautiful pearly sheen found on its cleavage faces. While it was originally thought to be a single mineral, modern mineralogy has since divided it into Stilbite-Ca and Stilbite-Na, though Stilbite-Ca remains the most common and sought-after form for collectors. Important Mines: The most breathtaking specimens of Stilbite in the world come from the Jalgaon and Nashik regions of Maharashtra, India. These basalt quarries produce massive, salmon-pink to cream-colored "bow-ties" that are world-renowned for their size and luster. Another historic source is the Bay of Fundy in Nova Scotia, Canada, and the Isle of Skye in Scotland. I always look for the Indian specimens for the vault, as their contrast against dark green Celadonite or Apophyllite creates a natural masterpiece that is hard to surpass. Mineralogical Profile Description: Stilbite is a hydrated sodium calcium aluminum silicate that crystallizes in the monoclinic system. It sits at a 3.5 to 4 on the Mohs scale, making it a delicate mineral that is primarily prized as a cabinet specimen. It is characterized by its vitreous to pearly luster and its signature sheaf-like or radiating habit. The crystals are often tabular and exhibit a distinct "pinacoidal" cleavage, which is where that beautiful pearly shimmer originates. While colorless or white is common, the presence of iron often tints the crystals into a highly desirable peach, salmon, or orange hue. It is a relatively light mineral with a porous structure, a hallmark of the zeolite group's ability to hold water molecules within its crystalline frame. Chemical Formula: (Ca,Na₂,K₂)₄Li₈Al₈Si₂₈O₇₂·28H₂O