Volcanoes - A constructive force

Volcanoes 

 Sakurajima, Japan – November 23, 2009. Photograph by KIMON BERLIN

  A mineral resource  

        A calm sunny day. All is well. Tourists are enjoying breakfast. Children run around, excited to start the day’s new adventures. A few mild tremors occurred during the night that most slept through. Suddenly, the ground trembles violently. Confusion and chaos ensues as people start scrambling for safety, not sure which direction they should go. Then the source is very apparent. Smoke and steam billows from the mountain in the distance. A volcano has erupted. People urgently evacuate away from the tyrant. Soon torrents of slow moving lava flow down the mountain. The peak explodes, sending lava, rocks, and ash high into the air. The searing hot particles will rain down on the unfortunate victims, with a scorching wind blowing across the land, burning everything in it’s path. 

   The initial eruption subsides, but steam and smoke still flow skyward from the now open mountain peak. This could last for days. The drama of survivors unfolds as the days pass.

   This is the scenario most people envision, when the term volcano is mentioned. It’s the stuff great movies are made of. Although they can be very destructive, they are constructive as well as being a vast resource of minerals, used for a multitude of applications. They are igneous and/or metamorphic in nature. Most people picture an ugly black rock that darkens the landscape. We will list a few of those products from one of the mightiest forces on Earth. 

    First, let us not forget that the Hawaiian islands were formed from volcanoes, as well as many others. Kilauea is one island that is still an active volcano and is growing day by day. The lava it produces is loaded with minerals the are super food for plant life. When the island settles and cools, plant life will quickly begin to flourish, thereby starting an Eco-system that thrives with a wide variety of plant and animal life. The lava rock is so potent that many hydroponics gardens utilize it as a growing medium. 

   All the iron we find on the crust of our Earth is the result of eons of volcano activity pulling it from the core.

            

Native iron.

    Hematite is also a metal pulled from the core.It is not ferris like iron, but is heavy and can be polished to a bright silver specimen.  

         

Hematite with polished pieces in front.

   Course pumice, from lava rock, is used as an abrasive in multiple venues, such sand paper, scale removal, and even for removing calluses. Other lava, such as pyro-clastic, form unique formations that can be very decorative in gardens, or even indoor decorations.

               

Lava rocks starting at top left - pyroclast,  Pumice,  2 pieces from Valley of fires in NM

   Glass known as Obsidian, is formed from extreme volcanic temperatures. It forms in four basic characteristics: black, mahogany, snowflake, and rainbow.

                  

Obsidian forms: top left - Mahogany  top right - Snowflake  lower right - Rainbow  lower left -  black

    Large sections have been cut to make counter and table tops. While it is very brittle, it can be polished to a high gloss shine. Native Americans used obsidian to make arrowheads, spear points, knives, and scrapers. A native American legend has spawned, from small droplets of obsidian that mingled with local calichi, calling them Apache tears. The carbon in the glass give it it’s black feature. Iron oxide contaminates produce Mahogany obsidian, and Crystals in the glass give the snowflake appearance in snowflake obsidian. The amount of carbon in the glass determines the density of obsidian. Heavy carbon creates opaque obsidian that allows no light to pass through. Lighter carbon density will allow for banding and translucence. On occasion the tranlucent obsidian will refract light passing through it to create a rainbow affect.

   Volcanoes produce air pockets in  surrounding molten rock formations. Moisture and mineral laden gasses escape from vents in volcanoes. When they reach a molten layer of rock, pressure pushes the rock upward slowly. As the rock cools and hardens, domes or columns are formed with the mineral rich gasses and water are trapped inside. Micro cracks allows moisture to escape over time, thus leaving the minerals to crystallize. When found these structures are cut at the base and cut in half and sold as “cathedrals” They make excellent collective pieces. 

                 

Amethyst cathedral from Brazil.

A similar item is called a geode. It is a molten “bubble” spewed from the volcano thousands of feet into the air. As it falls to the Earth, it cools and hardens. Mineral laden moisture is trapped inside. Again, cracks in the geode allow the moisture to escape leaving the minerals to crystallize. These are a favorite in rock shops, because it’s a mystery as to what you might find inside

Amethyst Geodes

   Few crystals are actually formed in inside a volcano. One of the most popular crystals is Peridot. It is a green crystal commonly mistaken as emerald. Large single peridot crystals are very rare and highly sought after by gemologists and jewelers. 

      

       Peridot cluster with single facetted crystals in foreground.

   These are just a few of the many products we are blessed with from the mighty and fearful volcano.