From the Rolling Stone article regarding his death:

Geoff Nicholls, Black Sabbath's longtime keyboardist who performed with the heavy metal legends for 25 years, died Saturday following a battle with lung cancer. He was 68.

"I'm so saddened to hear the loss of one of my dearest and closest friends Geoff Nicholls," Tony Iommi wrote on Facebook Saturday. "Geoff and I have always been very close and he has been a real true friend to me and supported me all the way for nearly 40 years. I will miss him dearly and he will live in my heart until we meet again. Rest in peace my dear friend." Quartz, Nicholls' previous band before he joined Black Sabbath in 1979, also confirmed Nicholls' death on Facebook. "Everyone in the band, and associated with the band, are struggling to find the words to express their feelings and sadness regarding the passing of their dear friend Geoff Nicholls earlier this morning at home," Quartz wrote.

"Geoff had been unwell for a long time battling cancer and had under gone extensive radio and chemotherapy plus other trial treatment but all sadly to no avail in the end. In this darkest and lowest moment of time Geoff's lyrics and music speak volumes to us and for us and through these his memory will live on forever."

Following a five-year stint with Quartz – whose self-titled debut was produced by Iommi – Nicholls, along with vocalist Ronnie James Dio, were recruited to join Black Sabbath following Ozzy Osbourne's firing in 1979.

Nicholls first appeared on Black Sabbath's 1980 LP Heaven and Hell – he's credited with crafting the menacing bassline for that album's classic title track – and remained with the band through nine studio albums, Live at the Hammersmith Odeon, world tours and a steady flow of lineup changes.

In 1985, Nicholls became an "official" member of Black Sabbath, a title he held intermittently until 1996, when Osbourne rejoined the band. Nicholls' tenure with Black Sabbath ended in 2004 when keyboardist Adam Wakeman, a member of Osbourne's touring unit, was hired to replace him in Sabbath.

"Very sad to hear of old friend and Sabbath keyboard player Geoff Nicholls passing. RIP Geoff," Black Sabbath's Geezer Butler wrote Saturday.

I'll be adding a Geoff Nicholls page on the wiki just for him!

Rest in peace, friend.