It's a fine metal and very corrosion resistant, but Green it is not. Apple declares leather not Green enough for their virtue signaling, then uses titanium?
1) Take ilmenite ore [from mining which Greens oppose] and boil in sulfuric acid [either from mining or as a byproduct of heavy oil refining] until it breaks down leaving you iron in solution and titanium dioxide.
2) Filter and dry the TiO2 then put it into a reactor. Heat to red heat, [requiring large amounts of fossil fuel energy] then add chlorine gas [produced by electrolysis of brine, which requires more energy].
3)The reaction is endothermic so ever so often you have to turn off the chlorine and reheat the reactor and remaining TiO2. [more energy]
4) Now you have titanium tetrachloride in a vapor and you can run that through a distillation column to clean it up. [the waste chlorides have to be neutralized and disposed of in a landfill]
5) The TiCl4 is now put into a closed container informally called the "the bomb" for reasons that will become obvious.
6) Now you add your choice of metallic sodium or metallic calcium, [either one produced by mining either salt or limestone, then processing it by electrolysis at high temperatures (700C for sodium) at great energy cost] close up the bomb and light it.
7) The resulting reaction is highly exothermic and after the vessel is done bouncing around you let it cool completely. [all that energy you have stuffed into the process is completely lost]
8) Open the vessel up and you have salt and titanium metal in sponge form. That gets lightly crushed and the salt washed away. [now you have dirty salt water to dispose of]
9) Take the Ti sponge and put it into either a vacuum induction furnace or an argon blanketed induction furnace. Melt it down, add alloying elements if any, and cast it under argon and now you have a useful piece of metal. [add even more energy]
If they wanted to signal their virtue they would use recycled steel or recycled stainless steel or recycled pop cans.
Although I can't think of anyway to actually set the phone on fire, titanium burns like fury. A class D fire extinguisher will not put it out. It wants to be an oxide again so bad it will burn sand, water or carbon dioxide.
A watchband made from a byproduct of dinner is much Greener.
And while I'm complaining, the new Finewoven cases, 2/3 recycled polyester, Green. 1/3 new plastic, not Green. Laminating it all together to make further recycling impossible, not Green.