Assertion: berkelium | /r/HasProperty | available
Facets:
value: in small quantities
type: OTHER
Source sentences:
text: Thus, 249Bk is the most accessible isotope of berkelium, which still is available only in small quantities (only 0.66 grams have been produced in the US over the period 1967–1983 ) at a high price of the order 185 USD per microgram.