RHODOCHROSITE WITH PYRITE

ABOUT THE SPECIMEN

Located in the Aomori Prefecture, in the far north of Japan's Honshu island, the Oppu Mine is one of the most famous Japanese localities in the mineral collecting world solely from the quality rhodochrosite that came from there. Here one can see richly colored botryoidal crystals layered across a sulfide matrix, with the underlying layer of pyrite visible in patches where the rhodochrosite stopped forming. The mine's primary operational lifespan lasted from back in the 17th century until 1979. Specimens of this style typically date to pre-WWII times, if not late 1800's, and examples of this size are rarely available. Oppu rhodochrosite is always highly sought after, and this is an exceptionally showy example why!

For reference, this specimen was valued by a former dealer at $7,000 a few years back, and they've only gotten rarer since then.

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MORE INFO

Oppu refers to a cluster of mining sites in the Shirakami mountain range that exploited epithermal fissure veins containing chalcopyrite, sphalerite, and galena within Neogene sedimentary rocks. Operations began in the late 1600s targeting silver, later shifting focus to copper and eventually lead-zinc-cadmium before final closure in 1979. Rhodochrosite formed from manganese-bearing hydrothermal solutions, typically appearing as botryoidal or reniform masses in rose-pink to deep red colors with translucent to semitranslucent character, often coating quartz or occurring with base metal sulfides. Oppu gained recognition as Japan's most significant rhodochrosite source, with banded material briefly remined in the 1980s for lapidary purposes. Most crystallized collector specimens predate World War II, making them over 80 years old. The characteristic waxy luster and saturated coloration of historical material from Oppu established it as the Japanese reference locality for the species, though authentic old specimens have become increasingly difficult to obtain.