![]() ![]() Mainly forming equilateral triangles, triangular shapes, and elongated blades, often with triangular terminations, like book pages, these occur within planes at different levels. The lattice patterns are caused by the lamellar twinning (twinning parallel to crystal planes) of orangey hematite and black magnetite inclusions. Semi-transparent with a colorless body color, Australian Lattice Sunstone’s aventurescence is caused by bright, citrus-hued hematite platelets, with smaller inclusions resulting in a subtle orangish-glow, and larger inclusions affording an attractive, glittery appearance. Its characteristic aventurescence aside, Sunstones’ key value determinant is transparency. ![]() From the Greek ‘iris’, meaning ‘rainbow’, iridescence is a rainbow-like color effect caused by a gems’ structure breaking up light into its spectral colors, which change depending on the angle of observation. Named for a Moonstone variety (Adularia) found in the European Alps, Adularescence is a deft whitish-sheen caused by interference phenomena (scattering of light by thin crystalline layers). ‘Schiller’ is derived from the Old High German ‘scilihen’, which means to blink or wink. Aptly coined the ‘Sunstone Effect’ or schiller, this beautiful sunlight phenomenon is caused by glittering, metallic inclusions reflecting light multiple times as it travels through the gemstone. According to legend, the workers exclaimed, “a ventura”, which means ‘by chance’, on noticing their glass with sparkles. In fact, the metallic iridescence in Labradorite is aptly called ‘labradorescence’.Īventurescence dates to an 18 th century Venetian glassworks, when copper filings accidentally fell into a batch of molten glass. While beautiful aventurescence defines Sunstone, adularescence is typically synonymous with Moonstone, and iridescence, Labradorite. Gems & Gemology Vol XXV - Spring 1989 p.47 ( ).Sister gem to Labradorite and Moonstone, Australian Lattice Sunstone is also known as Rainbow Lattice Sunstone. It is a rare occurrence when Sunstone occurs in a Moonstone, let alone with the added presence of the other phenomena seen in this extraordinary gemstone - perfect parallel lines and equilateral triangles which are incredibly rare in nature. The magnetite also predominantly forms triangles and even the lattice pattern has triangular terminations. ![]() The magnetite that has no alteration remains black with a metallic sheen. The magnetite inclusions in many cases have oxidized or altered through geophysical processes to give the iridescence or rainbow effect across the lattice patterning. These blades orientate (north/south) in different levels by a process known as lamellar twinning and also displays “Sagentic twinning”, which forms the lattice pattern. This forms as a very thin blades that occur in one plane at different levels (like pages in a book). Magnetite (Fe3O4) Iron Oxide which creates the lattice effect. This effect is called aventurescence, or Sunstone effect, and gives some of the gems their orange glow. Hematite (Fe2O3) - small, yellow to deep orange platelets which can be hexagonal shape and are generally in one plane within the Feldspar. With the advancement in technology over the last 3 decades, a recently conducted more in depth analysis has found the black blades and triangle inclusions in Rainbow Lattice to be magnetite.Ī paper with these results will be published soon by authors from the the Gemmological Institute, China University of Geosciences (Wuhan) and it will be published in The Journal of Gemmology by Gem-A. Whilst the initial testing of the stones inclusions conducted in 1989 (see ) concluded that the inclusions were made up of ilmenite (for the black blades and triangles) and hematite (for the orange platelets). The inclusions (internal features) are referred to as: the result of crystalographically oriented exsolution crystals within the feldspar mass. ![]() It is a type of feldspar which is predominantly Moonstone that is made up of 75% orthoclase and 25% albite. Rainbow Lattice is a very rare and unusual stone. ![]()
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