GREAT VALUE LOT 31.55 ct 6 pc NICKELINE – CANADA

Nickeline is a gemstone that carries the heavy, industrial weight of a deep metallic vein. A nickel arsenide, it was historically known as "Kupfernickel" because its warm, copper-red color often tricked ancient miners into thinking they had found a rich copper deposit. I have always been drawn to its "honest" metallic luster; it isn't flashy like gold, but it has a substantial, pale copper-pink hue that feels incredibly solid. While it is almost always opaque, I have worked with dense, massive specimens to create cabochons that take a mirror-like polish, looking more like a precision-engineered alloy than a natural mineral. It is a stone for the collector who appreciates the rugged, metallic chemistry of the Earth’s core elements.

Historical Significance: Nickeline holds a special place in the history of chemistry as the primary source of the element Nickel. Historically, German miners in the Erzgebirge mountains found it difficult to smelt and blamed "mischievous spirits" (nickels) for their failure to extract copper from the "false copper" (Kupfernickel). In 1751, Baron Axel Fredrik Cronstedt isolated a new metal from this mineral, which he named Nickel. In the world of fine minerals, it represents the birth of nickel metallurgy and stands as the definitive example of a simple but beautiful metallic arsenide. It is a bridge between the folklore of the medieval mines and the foundations of modern chemistry.

Discovery: While known to miners for centuries, the mineral was formally named Nickeline by François Sulpice Beudant in 1832 to reflect its nickel content. Its scientific classification as a hexagonal nickel arsenide helps explain its dense structure and the characteristic "tarnish" it can develop when exposed to air over long periods.

Important Mines: The most legendary and historic specimens come from the Erzgebirge region in Saxony, Germany, specifically Schneeberg. I also have a high regard for the massive, high-purity material found in the Cobalt-Gowganda district in Ontario, Canada, and the Bou Azzer district in Morocco. For the vault, I prioritize the Canadian material for its density and the German specimens for their incredible historical pedigree and sharp, though rare, crystal forms.

Description: Nickeline is a nickel arsenide that crystallizes in the hexagonal system. It sits at a 5 to 5.5 on the Mohs scale, making it a durable metallic stone that is capable of taking a very high, reflective polish. It is characterized by its metallic luster and its unmistakable pale copper-red or "pinkish-bronze" color.

One of its most identifying traits is its high density ($7.78$ to $7.8$ g/cm³), which gives even small pieces a surprising "heaviness" in the hand. It is often found as massive, metallic aggregates, but rare crystals can show a hexagonal habit. It has a metallic luster that can tarnish to a dull grey or black over time if not properly cared for. Because it is a nickel arsenide, it will give off a faint, characteristic garlic-like smell of arsenic if struck or heated—a classic "old-school" field test. When polished, it offers a unique, warm metallic glow that is entirely distinct from the brassy tones of Pyrite or the cold silver of Galena.

Chemical Formula: NiAs