Duncan’s departure was officially ascribed to being pretty burned out, though according to David Freiberg there were escalating drug problems. His farewell performances with the band were the studio recordings on Happy Trails and a live show on New Year's Eve 1969.
In January 1969 Valenti persuaded Duncan to move to New York and form a group with him; Duncan’s replacement was British pianist Nicky Hopkins, fresh from stints with Jeff Beck and Steve Miller. Hopkins had played on albums and singles by The Kinks, The Rolling Stones, The Who and his virtuoso piano boogie featured prominently on Shady Grove. By early 1970 Duncan was back, bringing Valenti with him. The new sextet issued Just for Love, and Fresh Air from the album gave them a Top 50 U.S. hit in 1970.
Hopkins left just before the release of What About Me, replaced by Mark Naftalin, formerly of the Paul Butterfield Blues Band and Mother Earth. Cipollina also left in October 1970 to form Copperhead with Jim Murray on vocals. A drug bust in 1971 took Freiberg out, and once he was released he did session work then joining Jefferson Starship in August 1972.
The remaining Quicksilver trio of Valenti, Duncan, and Elmore hired replacements and persevered through two more albums, Quicksilver and Comin’ Thru. Though the band didn’t break up, it was largely inactive from 1972 to 1975, when Valenti, Duncan, and Elmore recorded Solid Silver with cameos from Cipollina and Freiberg, whereupon Quicksilver more or less disbanded. Duncan put together another configuration in 1987 to record Peace by Piece, but the album went nowhere, and the band called it a day again.
John Cipollina continued to perform with a number of bands, including Welsh group Man and the Dinosaurs before he died from emphysema in 1989, aged 45. Valenti died in 1994 after surgery. Duncan returned again in the mid-’90s with yet another incarnation of Quicksilver.
But it’s the first two Quicksilver albums recorded by the quartet of Cipollina, Duncan, Elmore and Freiberg that are the high point of the group's career. The albums have a distinctive sound, based around extended arrangements and twin leads of Cipollina and Duncan. Cipollina plays in a highly melodic style, sparking off Gary Duncan's driving rhythm, a jazzier sound than the heavily amplified and overdriven sound of some of their contemporaries.