When you take something for granted, you assume it's always going to be there. The expression to take something for granite is a misspelling, unless you're talking to a rock, which would be weird.

The phrase take for granted has been around since the 1600s, so if it sounds old-fashioned, it is. It used to mean "not requiring proof" but now means something more like "not appreciated." You might take water for granted until you're really thirsty and can't find any. People take all kinds of things for granted, as shown in the examples below:

She was happy, absorbed — she seemed like a new, mysterious being to me then, someone outside the "mom" persona I took for granted. (Twilight)

"Do you see that, Ellie? Growing old is a terrible disease. Things you take for granted, you lose. Your ability to walk. Your vision. Your hearing. Even being able to go to the bathroom." (The Fourteenth Goldfish)

Granted and granite sound a lot alike, which is the only reason the eggcorn take for granite shows up anywhere. Granite is a speckled rock that is often polished and made into kitchen counters or monuments. If you take something for granite maybe you think the peel-and-stick on the counter is real? That's a stretch. Here are rock-solid examples of the word granite used the right way:

The kitchen is right off from the living room with white cabinets, granite countertops, and stainless-steel appliances. (The Hate U Give)

Nearby lay a rectangular cairn — hundreds of stones piled in the shape of an oversized grave with a granite obelisk for a headstone. (Blood of Olympus)

Shake the rocks out of your head and don't take anything for granted. Take a deep breath and be thankful!