Osmiridium

Behold mortal, the most expensive "ore" in the mod (you need to sacrifice a Gerald for this very ore).

Osmiridium is a naturally occurring alloy between Osmium (element #76) and Iridium (element #77), thus the portmanteau. It is possibly the densest material in all of NTM, somehow, possibly even exceeding Dineutronium.

Overview
You can obtain this from Osmiridium-infused tektite. You can't get this right off the bat, you need to refine it FOUR times.

Refining
Step 1: Find an Osmiridium-infused tektite ore at the detonation site, they're pretty much unmissable.

Step 2: Collect them and bring them to your local shredder.

Step 3: Get the tektite powder it makes.

Step 4: Bring them to your local centrifuge.

Step 5: Ignore everything else it makes, the one you need is the small paleogenite powder.

Step 6: Combine the small powders into normal powders and bring them to your local chemplant.

Step 7: Gather 8 Fluorite, 4 Bismuth nuggets, 1,000mb Hydrogen Peroxide, and said powder.

Step 8: Process it, it should make Osmiridic Solution, these can only be carried by hazardous material barrels.

Step 9: Get it's fluid identifier and slap it in your local SILEX (pretty sure you need gamma for this).

Step 10: Process all of the solution, it should make impure osmiridium powder. (100% chance hell yeah).

Step 11: Slap the powder in your local crystallizer/acidizer and wait until it becomes crystals (effectiveness upgrade VERY recommended).

Step 12: Slap the crystals into your local furnace and profit an insane amount of 1 ingot/crystal.