Lisa Rinna's mother, Lois Rinna, is dead ... a few days after suffering a second stroke.
Lisa's mom died Monday morning ... according to Amelia Hamlin, Lisa's daughter and Lois' granddaughter.
The cause of death is unclear but Lisa went public last week with the news her mom had suffered another stroke -- Lois previously suffered a stroke back in 2013 -- getting emotional on social media over what was going on with her mom.
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Amelia posted a heartfelt tribute to Lois on Monday, along with a ton of pictures of the family with her "guardian angel."
The model is remembering her late grandma as her best friend, her strength, her rock, her everything ... and she says Lois' "laughter never failed to light up any room you ever walked in."
Amelia is also thanking Lois for being the strength their family needed, and for teaching her what it means to be a strong woman.
You might have seen Lois on TV before ... she made a habit of appearing on "Real Housewives of Beverly Hills" over the years with Lisa.
Amelia mentions 5:05 AM in her goodbye post ... which appears to be the time of death.