UMG Purification. Photo Courtesy of Calisolar. Polysilicon prices are on the rise again in the solar PV industry, and metallurgically purified polysilicon (UMG) is back in the news. This time, however, UMG is generating interest for strategic market access rather than supply diversification. Download PDF (right-click, save-as) PHOTON Magazine: UMG U-Turn Originally Published in PHOTON International, November 2010. Provided with...