BLACK JADE SPHERE
A beautiful highly polished Black Jade Sphere. With a reflective surface like a mirror, you can see my reflection taking the photos. This is a Nephrite Black Jade Sphere from Western Australia. Jade is one of the many mineral treasures found in this vast land of Australia. These are not readily available and we never know if we can source more. It is iron impurities that adds the intense blackness to this jade. An essential for any jade or Aussie mineral collection. Great properties all round. Difficult to photograph with its highly reflective surface. Due to the very fine tight knit grain it takes one of the highest polishes of any stone. This sphere has a few characteristic white marks often visible in nephrite jade.
7.3cm in diameter, 601g.
Nephrite is a rock comprising mostly massive microcrystalline to cryptocrystalline felted amphiboles of the tremolite – actinolite series. It is one of the two rocks termed as jade, the other being jadeitite or jadeite jade, consisting mostly of jadeite. Both are extremely tough and resistant to fracture such that they have been used for making choppers and blades since Neolithic times. In addition to amphibole, nephrite can contain minor to trace amounts of the following. Diopside, grossularitic garnet, magnetite, chromite, graphite, apatite, rutile, pyrite, datolite, vesuvianite, prehnite, talc, the serpentine polymorphs and titanite.
Nephrite is actually not a mineral, but a variety of the mineral actinolite. The nephrite variety is composed of fibrous crystals inter-twinned in a tough compact mass. Other actinolite varieties are quite different from nephrite. The toughness of jade is remarkable. It has a strength greater than steel and was put to work by many early civilizations for axes, knives and weapons. It was later that jade became a symbolic stone used in ornaments and other religious artifacts.