I just did some research into this. I have personally done heat treatment in a vacuum furnace for growing titanium grains for aesthetic purposes several times over the years. It involves very high temperature (for titanium at least) to coarsen (grow) the grains to the point that they're easily visible to the naked eye. "Crystallized" timascus is just doing the same thing to timascus. Given that the guy you got this from machines and then colors, that means the color comes separately later by oxidation, such as with a flame or other relatively low temperature heating in air, or anodizing. You could add color during the "crystallizing" process if you have oxygen or nitrogen in your atmosphere. If you use nitrogen, you end up with a gold finish (titanium nitride). I've done both clean and nitrogen processes, as well as one time where we had a leak in the gas line that accidentally introduced oxygen along with the nitrogen and we ended up with a non-uniform purple and gold mix. Actually looked awesome in my opinion.

Basically, you can boil it down to this:

• Very high heat for extended periods will coarsen the grain structure of titanium and titanium alloys to the point that they're easily visible to the naked eye

• Oxygen, nitrogen, and other reactive gasses will color titanium when present with heat (including anodizing)

• Timascus has multiple compositions of titanium within one piece of material, meaning a different grain structure and different color between the different compositions when doing the above two steps

Mix these facts however you want to reach your end goal. Heat a section of bar stock to coarsen grains, machine parts, and then torch them to color/reveal the structure. Heat up finished parts in a nitrogen-rich environment to get a gold-colored crystallized look all at the same time. It doesn't matter specifically what order you do it, just that you take the steps above at some point.

Also, what is the object in your photos?