BLACK JADE SPHERE
A beautiful highly polished Black Jade Sphere Large size. 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.
9.3cm in diameter, 1253g.[/vc_column_text]
Jade is the name for two different stones. Realized in 1863, they are both still called Jade.
Toughest Natural Stone in the World
The toughness of Nephrite Jade is remarkable. It has a strength greater than steel when 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 of history. Jadeite is usually green to grayish green, white, pale shades of blue or purple, may also be yellow or pink. Nephrite colors are black, green and white.
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. 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.
A variety of Actinolite, Nephrite is Jade. Used for generations in New Zealand, China and Central America as an ornamental stone. Revered as a stone of deep significance and cultural associations. It’s a hard heavy and tough as nails stone. The polish and reflection of color on Black Jade is a mirror.
Actinolite is a relatively common mineral in some metamorphic rocks. It belongs to a series with the minerals tremolite and ferro-actinolite. A series occurs when ions can freely substitute between each other. In this case, when iron is predominant the mineral is ferro-actinolite and when magnesium is predominant the mineral is tremolite. Actinolite is the intermediate member.
Actinolite occasionally forms interesting crystal habits and specimens. Crystals can be similar to hornblende, but are always translucent or even transparent. Typically they are prismatic, flattened and elongated. Crystal specimens of Actinolite can make very interesting mineral specimens.
Color is usually green, white or black.
Luster is vitreous.
Transparency: examples are translucent to transparent.
Crystal System is monoclinic; 2/m
Crystal Habits flattened prismatic and elongated crystal with a dome like termination, two of the four faces of a prism. Also as a fibrous mass (asbestos) and as a fibrous and very compact mass (nephrite jade).
Cleavage: is perfect in two directions at close to 60- and 120-degree angles.
Fracture is splintery to uneven.
Hardness is 5.5 – 6.
Specific Gravity is approximately 2.9 – 3.3 (very slightly above average for translucent minerals).
Streak is white.
Associated Minerals are quartz, lawsaonite, epidote and glaucophane.
Other Characteristics: the compact nephrite variety is extremely tough and is actually stronger than steel.
Notable Occurrences include the Lake Baikal Region, Russia; China; New Zealand; British Columbia, Canada, Australia, USA, Guatemala and Taiwan.
Best Field Indicators are toughness (nephrite jade), fibrosity (asbestos), typical green color, crystal habit and hardness.
Chemistry: Ca2(Mg, Fe)5Si8O22(OH)2 , Calcium Magnesium Iron Silicate Hydroxide.
Uses: as ornamental stone used for carvings and semi precious to precious stone used in jewelry