Dravite



Dravite, a sodium magnesium aluminum boron silicate hydroxide mineral of the tourmaline group, is uncommon at Franklin. One specimen has been analyzed and found to be dravite (Dunn et al. 1977). These crystals are dark green, 25 mm in length, composed of trigonal prisms and pedions, and markedly prismatic in habit, quite unlike the common equant habit of most Franklin uvite. They are associated with calcite and pyrrhotite from the Franklin Marble. Black ferrian dravite which occurs as massive material associated with quartz on the 1600 level of the Sterling Mine. (Dunn, 1995)

 Location Found: Franklin and Ogdensburg
     
 
 Year Discovered: 1883
     
 Formula: Na(Mg3)Al6(Si6O18)(BO3)3(OH)3(OH)
 Essential Elements: Aluminum, Boron, Hydrogen, Magnesium, Oxygen, Silicon, Sodium
 All Elements in Formula: Aluminum, Boron, Hydrogen, Magnesium, Oxygen, Silicon, Sodium
     
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
     
     
 To find out more about this mineral at minDat's website, follow this link   Dravite

     
 References:
Dunn, Pete J. (1995). Franklin and Sterling Hill New Jersey: the world's most magnificent mineral deposits. Franklin, NJ.: The Franklin-Ogdensburg Mineralogical Society. p.424


The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 27 No. 2 - Fall 1986, pg. 10Minerals of the Franklin Quarry, Philip P. Betancourt, Tourmaline Group (uvite and/or dravite)
View IssueV. 21, No. 1 - March 1980, pg. 8Mineral Notes Research Reports, Uvite
     
Images

     
Dravite tourmaline and calcite, Sterling Hill Mine, Ogdensburg, NJ
Dravite tourmaline (black prismatic crystals) and calcite (white) from the 1060 crosscut, 700 ft level, Sterling Hill Mine, Ogdensburg, NJ. Field of view 3 1/4". From the collection of JVF, and photo by WP.







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