Argyle diamond mine of tunnelling, the Argyle underground block cave development was officially completed. In 2013, Argyle is estimated to produce 10.2 million carats with an average per carat price of $25/carat. The Argyle diamond mine is also notable for being the first successful commercial diamond mine exploiting a volcanic pipe of lamproite, rather than the more usual kimberlite pipe; much earlier attempts to mine diamonds from a lamproite pipe in Arkansas, USA were commercially unsuccessful. The Argyle mine is owned by the Rio Tinto Group, a diversified mining company which also owns the Diavik Diamond Mine in Canada and the Murowa Diamond
Diamond in the Rough (album) Diamond in the Rough (album) Diamond in the Rough is the fourth studio album released by American country artist Jessi Colter. It was the second album issued by Colter in 1976; the previous was "Jessi", released earlier in the year. "Diamond in the Rough" was issued under Capitol Records and was produced by Ken Mansfield. "Diamond in the Rough" was issued as Colter's second studio album in 1976, containing ten new tracks, which included a cover of The Beatles's "Hey Jude". The album only spawned one single released in 1977, titled "I Thought I Heard You Calling My Name", which