The Oppu Mine remains, long after its closure, the classic and most well known source of rhodochrosite from Japan. Specimens typically consist of botryoidal rhodochrosite. However, in the Marion Stuart collection about 10 years ago, I saw this fantastic large specimen of botryoidal rhodochrosite covering large, fat quartz crystals. To this day, for this style, I still have not seen another like this for overall size and quality. Although one cannot say when it was mined, these specimens came out prior to WWII and I have seen many dated to the late 1800s from old collections in museums now. Ex. Marion Stuart Collection.