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Showing posts with label spessartine. Show all posts
Showing posts with label spessartine. Show all posts

Tuesday, November 17, 2015

Red Ember Mine in Massachusetts: "Gar"-net Almandine Versus Trout Almondine

     Red Ember Mine garnets were discovered in the last six years in the town of Erving in Franklin County in western Massachusetts.




     The spectacular gems are highlighted and backlit in the surrounding black graphite matrix in the above image. Without the backlighting they appear more purplish in color:




         Garnets are a group of nesosilicate minerals that are used both as gemstones and as abrasives. The 6 different types of garnets are pyrope, almandine, spessartine, grossular, uvarovite and andradite. The Red Ember Mine garnets are primarily almandine (hence "gar" (the fish) net almandine.) No, no fishnets are involved. ;-)




      The first three garnet types are in one solid solution series and the last three are in another. Neither series is associated with trout almondine :-).



      The word garnet is derived from its color. The deep red color of some garnets reminded the French of a red-skinned fruit. In early French, the fruit was called pomme grenate or "seedy apple." This later became pomegranate in English.




      The early French word grenate, meaning "seedy," is the source of the adjective grenat, meaning "red like a pomegranate." This word was then used as a noun to refer to the deep-red gemstone. When transferred into English, grenat became garnet. 

         As we've discussed here at PEOTS before, color is not a reliable mineral characteristic. Garnet actually occurs in a variety of colors from red to orange to yellow to green to indigo to violet. Blue garnets are extremely rare and tend toward indigo:




             A black to gray graphite matrix for garnets, as in western Massachusetts, 



shows off the garnets extraordinarily:



       Have you seen garnets in colors other than pomegranate? Or, perhaps, have you seen the Red Ember Mine garnets? I sense another field trip in our future. . .

        And here's an image of the "Subway Garnet" (or whatever you'd like to call it) found in Manhattan, NYC, and housed at the American Museum of Natural History:





Emberly yours,
Steph


P.S. Speaking of field trips, here are a few images of cryptobiotic soil from David in Utah as well as one bodacious cairn:



      






And multiple multiple cairns: