In reading about the analysis of the rock Jake that Curiosity test, I ran into a lot of complicates language. Had to put my head out the window and scream type of language.
Basically, the rock Jake and the rocks called feldspar are quite a bit alike. Feldspar is from magma, which comes from volcanoes. The type of feldspar, and there are a ton of types, is called igneous.
Igneous is a form of crystallized rock from magma and from there, you are on your own.

Curiosity also scooped a bit of soil and ran it through the hopper. No results on what is in the soil yet.

A map of the world, this one, where feldspar is found.

By, Anwar saadat, English Wikipedia

A NASA diagram of Curiosity.

The now famous rock, Jake.

Jake again when Curiosity put her hand on it.

This is a piece of feldspar on earth, in PortugalĀ  by, Chmee2, Wikipedia Commons.

This is a picture of the soil sampler on Curiosity when she was still in the lab on Earth.

A picture that NASA made to show where they tested Jake.

Now, for the soil samples.
Two diagrams of the soil sampler on Curiosity.

This is a picture of the sampler on Curiosity in the lab on Earth.

Curiosity roughed up a bit of soils with her front wheel.

The result.

The last picture is of Curiosity holding a sample of soil in her scoop.