For connected and emissive textures Optifine required.
I was inspired by Ore Highlighter created by Zyrphox and Visible Ores created by Techy69.
Mod support:
Galacticraft Core (Galacticraft Planets in thoughts);
Immersive Engineering;
Tinkers Construct;
Thermal Foundation.
Note: If you get "OpenGL Error: 1281 (Invalid value)" go to Video Settings > Performance and set "Render regions" to OFF (source)