How can chemists distinguish pure chemical element specimens that look almost "the same" as well as what deposit is what in a multimineral mined rock? As a non chemist I am most often charmed when visiting Wikipedia articles of chemical elements and see images of very pure specimens of element after element, proton by proton, and often also metal cube specimen made from smithing similar pure deposits.

The wiki article Periodic table allows me to do so easily; here are some elements I found looking almost the same and don't think I personally could distinguish between them without some instrument:


molybdenum and manganase
titanium and chromium
rutenium and cadmium
sodium and aluminium
silicone and germanium


My problem

Generally all examples are of synthetic specimens of about 99.9% purity but that me to wonder what test can a chemist make in a natural environment, say inside a natural cavemine, to determine which natural deposit contains what after the mining and positioning a seemingly multimineral natural deposit;
Of course, I understand that with natural deposits of mainly carbon or copper, or iron (water exposed and rusty) natural deposits, let alone with very pure specimens of these elements, it will be easy because of color, but I believe that generally or mostly color by itself won't be enough due to various color biases and I assume that today there are in-place very-accurate tests that can be done, especially for different parts of a multimineral deposits.

My question

How can chemists distinguish pure chemical element specimens that look almost "the same" as well as what deposit is what in a multimineral mined rock?
What you're describing is essentially the field of "qualitative inorganic analysis". That's a very broad subject, but a short description is that prior to the advent of advanced instrumentation, chemists developed extensive series of tests specifically to determine the elemental composition of samples.

For example, one would start with basic physical properties like color, density, and hardness, then look at reactions with heat, acids, bases, oxidants, etc. If the compound could be solubilized in any way, then one can look at how the solubility/color/etc is affected by addition of known cations and anions. If it was a geological specimen, then the location and the types of surrounding minerals would help inform the analysis as well.

A well trained inorganic chemist would have standard flow-charts of tests and could fairly confidently identify the elemental composition of common minerals and metals.