UU-Matter is made by the Mass Fabricator in exchange of EU and can be used to craft into various resources. Using UU-matter is the only way to obtain Iridium ore , which is used for Iridium Plates for the Quantum Armor set.
UU-Matter is created in the Mass Fabricator as shown above. Creating a single UU-Matter requires 1,000,000 EU. Putting Scrap into the lower slot will provide an "amplifier" for the next 5000 EU the Mass Fabricator consumes, speeding up the process by 6x, thus only requiring about 166,666 EU per UU-Matter.
Here, UU-Matter is arranged in distinctive ways in the crafting grid to create items that range from Grass Blocks to Diamonds. Recipes are not shown on Industrial wiki. You should find these recipes by yourself.