One of Amy Grant’s favorite stories is about philosophy and Minnie Pearl. The country comedienne, whose real name was Sarah Cannon, asked Grant the most important color in the artist’s palette. Grant admits to mentally sprinting through the 64-color Crayola box — indigo? apricot? scarlet? — but Cannon had her own answer. The most important color, Cannon said, was black: Black is the color that gives depth and shading.

(Yes, this is the Minnie Pearl of “How-dee!” and the hat with the dangling price tag. Offstage, she was whip-smart.) Grant is an entertainer who uses a lot of black in her book Mosaic: Pieces of My Life So Far (Doubleday/Flying Dolphin Press, $24.95), the release of which coincides with her new Greatest Hits album. It turns out that if you get Grant going for longer than the three minutes of the average song, she’s got a lot more shades of gray in her personal palette.

Grant, 47, says that blending her three kids from her first marriage with husband Vince Gill’s daughter Jenny was no picnic. She writes about the kids’ grim faces at the wedding and rails about those who assume celebrities get an effortless happily-ever-after. Blended families are tough sledding, she says, even when you’re married to your best friend.

She admits to depression and quotes Winston Churchill, calling the disease the “black dog.” She writes about spending an afternoon with a California street person. She even talks about what pregnancy does to a singer’s supporting muscles. But she doesn’t have a bad word to say about her ex-husband, Christian singer Gary Chapman. Her most lacerating comments are about plants: Suffice it to say that Grant is no fan of purple thistles. You won’t be seeing this kind of trash-talking on TMZ.