A photomicrograph of the first isolated bulk (1.7 micrograms) sample of berkelium. The lump is 100 μm across.
<a rel="nofollow" class="external text" href="http://gotexassoccer.com/elements/097Bk/Bk.htm">Oak Ridge National Laboratory</a>, US Department of Energy
circa 1971 <div style="display: none;">date QS:P,+1971-00-00T00:00:00Z/9,P1480,Q5727902</div>
<cite class="book" style="font-style:normal">"The Chemistry of Berkelium" in   (1984) <i> <a rel="nofollow" class="external text" href="https://books.google.com/books?id=U-YOlLVuV1YC&amp;pg=PA42">Advances in Inorganic Chemistry and Radiochemistry</a></i>, 28, <a href="https://en.wikipedia.org/wiki/en:Orlando,_Florida" class="extiw" title="w:en:Orlando, Florida"><span title="city in and county seat of Orange County, Florida, United States">Orlando</span></a>:  Academic Press Inc., p. 42  <small><a href="https://en.wikipedia.org/wiki/International_Standard_Book_Number" class="extiw" title="en:International Standard Book Number">ISBN</a>:  <a href="//commons.wikimedia.org/wiki/Special:BookSources/0120236281" title="Special:BookSources/0120236281">0120236281</a>. </small>  <span class="language">"Figure 7"</span></cite>