<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>Anna Hietanen</dc:creator>
  <dc:date>1987</dc:date>
  <dc:description>&lt;p&gt;Tourmaline (dravite) from a layered two-plagioclase anorthosite in the Boehls Butte quadrangle, Idaho, has the following structural formula: (Na&lt;sub&gt;0.55&lt;/sub&gt;Ca&lt;sub&gt;0.17&lt;/sub&gt;)&lt;sub&gt;0.72&lt;/sub&gt;(Mg&lt;sub&gt;1.96&lt;/sub&gt;Fe&lt;sub&gt;0.57&lt;/sub&gt;Mn&lt;sub&gt;0.01&lt;/sub&gt;Ti&lt;sub&gt;0.04&lt;/sub&gt;V&lt;sub&gt;0.03&lt;/sub&gt;Al&lt;sub&gt;0.47&lt;/sub&gt;)&lt;sub&gt;3.08&lt;/sub&gt;Al&lt;sub&gt;6&lt;/sub&gt;(BO&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;3.02&lt;/sub&gt;Si&lt;sub&gt;5.98&lt;/sub&gt;O&lt;sub&gt;18&lt;/sub&gt;(OH,F)&lt;sub&gt;3.35&lt;/sub&gt;. The indices of refraction are &lt;span&gt;ω&lt;/span&gt; = 1.647(1) and &lt;span&gt;ε&lt;/span&gt; = 1.621(1), and the unit cell parameters are &lt;i&gt;a&lt;/i&gt; = 15.9425(6) and &lt;i&gt;c&lt;/i&gt; = 7.1883(3). &lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.17741/bgsf/59.2.002</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Geological Society of Finland</dc:publisher>
  <dc:title>Tourmaline (dravite) from the Boehls Butte anorthosite, Idaho, U.S.A.</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>