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Every Snowflake is Different!
Although all snowflakes have a hexagonal shape, other details of their geometry can vary. These variations are produced by different temperature and humidity conditions through which the snowflake falls. Some temperature/humidity combinations produce flakes with long needle-like arms. Other conditions produce flakes with wide flat arms. Other conditions produce thin, branching arms. These different shapes…
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The Snowflake Grows as it Falls
The newly-formed ice crystal (snowflake) is heavier than the surrounding air and it begins falling. As it falls towards Earth through humid air, more water vapor freezes onto the surface of the tiny crystal. This freezing process is very systematic. The water molecules of the vapor arrange themselves so that the hexagonal crystal structure of…
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A Tiny Particle High in Earth’s Atmosphere
A snowflake begins when a tiny dust or pollen particle comes into contact with water vapor high in Earth’s atmosphere. The water vapor coats the tiny particle and freezes into a tiny crystal of ice. This tiny crystal will be the “seed” from which a snowflake will grow. Hexagonal “Mineral” Crystals The molecules of water…
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Use of Serpentine: CO2 Sequestration
Serpentinite rock units have been considered as repositories for the disposal of waste carbon dioxide produced when fossil fuels are burned. Injecting carbon dioxide into subsurface rock units in the presence of water can produce magnesium carbonate and quartz in an exothermic reaction similar to the one shown below. Mg3Si2O5(OH)4 + 3CO2 + H2O –> 3MgCO3 + 2SiO2 +…
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Use of Serpentine: Sculptures
Some varieties of serpentine can be carved into beautiful stone sculptures. Fine-grained, translucent material with a uniform texture and without voids and fractures is preferred. Serpentine is relatively soft and carves easily. It also accepts a nice polish. Serpentine sculptures range in size from under one centimeter to several meters in height. Bowls, vases, desk…
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Use of Serpentine: Gemstones
Attractive serpentine can be cut into a wide variety of gemstones. It is most often cut into cabochons and beads. They usually display a range of green, yellow, and black colors and often have magnetite, chromite, or other minerals as interesting inclusions. The lower left side of the green and black cabochon in the center of the photo…
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Use of Serpentine: Asbestos
Some varieties of serpentine have a fibrous habit. These fibers resist the transfer of heat, do not burn, and serve as excellent insulators. The serpentine mineral chrysotile is common, found in many parts of the world, is easily mined, and can be processed to recover the heat-resistant fibers. The use of chrysotile and other serpentine minerals…
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Use of Serpentine: Architectural Material
Serpentine has been used as an architectural stone for thousands of years. It is available in a wide variety of green and greenish colors, often has an attractive pattern, works easily, and polishes to a nice luster. It has a Mohs hardness of 3 to 6 which is softer than granite, and usually harder than most marble. This low…
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Physical Properties of Serpentine
The most obvious physical properties of serpentine are its green color, patterned appearance, and slippery feel. These remind the observer of a snake and that is where the name “serpentine” was derived. Serpentine is also known for its translucent diaphaneity, waxy luster, ease of being cut into shapes, and its ability to accept a polish. These…
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Serpentinites and Serpentine Formation
Serpentine minerals form where peridotite, dunite, and other ultramafic rocks undergo hydrothermal metamorphism. Ultramafic rocks are rare at Earth’s surface but are abundant at the oceanic moho, the boundary between the base of the oceanic crust and the upper mantle. They are metamorphosed at convergent plate boundaries where an oceanic plate is pushed down into the mantle. This is…