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Written by Maddy Sunday, October 20, 2019

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1 - Hydrogen - H
2 - Helium - He
3 - Lithium - Li
77 - Iridium - Ir
83 - Bismuth - Bi

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Labradorite , Albite , Spectrolite , Anorthite

Labradorite from Australia Labradorite is a feldspar mineral in the category tectosilicate. It has an anorthite percentage (%An) of between 50 to 70%; Anorthite is the calcium endmember of the plagioclase feldspar mineral with the formula of pure anorthite CaAl 2 Si 2 O 8 ; found in mafic igneous rocks; a rare mineral on Earth but abundant on the Moon. Twinning is common. Labradorite displays an iridescent optical effect or schiller known as labradorescence making the mineral glow with yellow, green and blue by rotating it in different angles. The cause of this optical phenomenon is phase exolution lamellar structure, occurring in the Boggild miscibility gap. Effect visible when the lamellar separation is between 128 and 252 nm, the lamellae are not necessarily parallel; and the lamellar structure is found to lack long range order. The lamellar separation only occurs in plagioclases of a certain composition in particular, those of calcic labradorite and bytownite

Fluorescence

Fluorescence is the propriety of a mineral to emit light when is illuminated with ultraviolet light. Fluorescence happen when an electron of an atom is hit by a high energy photon and its orbit jumps to a higher orbit absorbing the photon. After that, the electron will jump back to its orbit but the energy accumulated will be released by heat and another photon. On phosphorescence, the electrons jump more orbits higher and will fall slowly each orbit until its gets to the original orbit, releasing light over time. Fluorescence happens (the drop of the electron to its original orbit) typically in just 10 nanoseconds but phosphorescence can last seconds to minutes or even more. When higher energy light hits a mineral, if that minerals contains some specific activators (impurities), then it will convert some of the incoming light to another, less energetic light. Ultraviolet light is usually the best way to show this effect. Ultraviolet light has a wavelength from 10 to 400 nm and i

Cerussite

A specimen of cerussite from Maroc Cerussite is a Lead Carbonate and an important lead ore. The name comes from latin cerussa, means white lead. Cerussite is isomorphous with aragonite. Like aragonite, it is very frequently twinned (occurs when two separate crystals share some of the crystal lattice points in a symmetrical manner). Three crystals are usually twinned together on two faces of the prism, producing six-rayed stellate groups with the individual crystal intercrossing at angle of nearly 60 degree. Usually is colorless or white, sometimes grey or greenish from transparent to translucent and adamantine luster. Cerussite from certain locations is rich in silver and may be used as minor silver ore. Uses: lead plaints, lead source and cosmetics throughout history Characteristics Group Carbonate - Lead Carbonate Formula PbCO 3 Variable formula: (Pb,Ag,Cr)CO 3 Lead 77,54%; Carbon 4,49%; Oxygen 17,96% Crystal system Orthorhombic Color: white, colorless, gr

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