Anyone know which Photoshop tool can be used to create something like this beautiful piece? Not looking to copy only looking for the tool. Any help is appreciated. Thanks so much!

[GAPeachytoo_]

[Mylenium]

No tool, vector blur based filters such as smudge or some of the painterly styles, combined wih heavy color adjustments and possibly other effects.

Mylenium

[Trevor.Dennis]

Yes.  It uses what are called Impasto brushes.  According to Kyle Webster, his impasto brushes will be available for free after he has revamped them. 

Are Kyle Webster impasto brushes now free with Creative Cloud?

However, I have just looked and they are not included in his additional brush pucks at this time.

Adobe Photoshop CC | Download exclusive brushes from Kyle T. Webster

John Derry also has an Impasto brush set available for sale

The PixlBlog: John's Impasto! for Photoshop Released

[Trevor.Dennis]

A very quick and dirty play.

Work with lots of layers (about half a dozen) and add a small Bevel and Emboss layer style to each layer.  The easiest way is to make one layer, add some brush strokes, and then apply the Bevel & Emboss.  When you happy, copy that layer once, and delete everything (Ctrl A > Delete) then copy the empty layer with the layer style a few more times.

Experiment with available brushes, but the Kyle Webster brushes are best.  Use darker tones on the lowest layers and lighter at the top.

When you get something you like, apply Filter > Stylize > Oil Paint with high settings.

The Oil Paint filter all by itself produces interesting results if you go OTT with it.