Quartz

specimen number:
1052558

location:
Otomezaka mine, Otome mine, Kurobera, Kofu, Kinpuzan, Yamanashi, Japan

description:
Very fine choice old Japanese classic. A loose glassy and gemmy Japan law twin quartz crystal grouping without matrix. Very little micro-damage present, considering the size of this crystal grouping this is in very good condition. The specimen comes with an antique label as shown at the end of the video and dates to the very early 20th century. The specimen was originally acquired through famous German dealership Dr. F. Krantz.

The Otomezaka mine, also known as the Otome mine, is located in the Kurobera area of Kofu City within the Yamanashi Prefecture of Japan, a region historically famous for its high-quality rock crystals. Geologically, the deposit consists of hydrothermal quartz veins hosted within the Kinpuzan granitic pluton, which provided the heat and silica-rich fluids necessary for crystal growth during the Miocene epoch. Historically, mining in the Yamanashi region dates back hundreds of years, but the Otome mine saw its most significant commercial activity from the mid-1800s through the early 20th century, particularly to support the local gemstone and optical industries. The site is internationally renowned as the classic locality for Japan-law twin quartz crystals, which are defined by two individual crystals joined at a specific angle of 84 degrees and 33 minutes. These twins are typically flattened or heart-shaped and are considered some of the finest examples of this twinning law in the world due to their exceptional transparency and sharp morphology. Although large-scale mining operations have long since ceased, the Otome mine remains a primary reference point for Japanese mineralogy and the study of quartz crystallization.

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