Jade rock

Jade: The Green Gold

Jade is a mineral predominantly known for its green color. The jade mineral can also appear naturally in other colors such as white and yellow. It is popularly used in artworks from Southeast Asia, East Asia, and South Asia. In Japan, it was used for jade bracelets and was a symbol of wealth and power. Leaders also used jade for rituals and was considered the national stone.

Jade pendant

Jade pendant.

Nephrite and jadeite

In 1863, French mineralogist Alexis Damour discovered that jade could be one of two different minerals, nephrite or jadeite.

Nephrite is made up of monocrystalline interlocking fibrous matrix of the amphibole mineral series tremolite, which is rich in calcium and magnesium-iron. Tremolite occurs in metamorphosed dolomitic limestones and Actinolite. The higher the iron content, the greener the color of the mineral.

Jadeite is made from pyroxene which is rich in sodium and aluminum. It is the more precious type of jade as it forms through microcrystalline interlocking growth of crystals rather than the fibrous kind which only occurs in metamorphic rocks. This makes nephrite slightly softer than jadeite.

Hisui Kaigan

Hisui Kaigan, the “Jade Coast”.

The Jade Coast of Japan

The city of Itoigawa, Niigata Prefecture is known to be one of the oldest jade -producing regions in the entire world. The city’s geological position is where the Fossa Magna and the Itoigawa-Shizuoka Tectonic Line meet. This made for a perfect recipe in allowing a cornucopia of minerals to gather from the mountain ranges from the east some 20 to 500 million years ago. The minerals that were often smoothed over by the current were carried by rivers such as the Himekawa to the coast of Itoigawa.

Hisui Kaigan, also known as the Jade Coast, is comprised of pebbly beaches where rare minerals such as jade can be found. Up until the end of the 20th century, jade was so common and abundant on the beaches of Kotakigawa Jade Gorge and Hisui Kaigan that locals had the luxury of being able to choose only high-quality jade.

Today, it is more difficult to find precious minerals on the shores of Itoigawa. It is strictly prohibited to pick jade in the Kotakigawa Jade Gorge but it is still allowed in the Jade Coast. If you patiently scour the shore, you may be able to find jadeite pebbles scattered about. What a fun way to spend a day!