I think it's no coincidence that we cull crystals and ore from "veins."
If the Earth has a circulation system, surely it's not our riverways and oceans. Our Earth's veins are the metals and crystals that honeycomb the planet. They're filled with copper, and gold, and gemstones, and minerals. They're tangled up under our feet in every color and texture.
Sharp, opaque, vitreus, or soft, our Earth's blood vibrates.
And we collect its blood, we mine these "veins," and take a piece of the whole.
In a way, we make a sacrifice of the Earth for some kind of goal. Beauty, adornment, peace, enlightenment, science - whatever you're getting from holding a drop of the Earth's blood in your hands, show it the same respect and appreciation as you do your own blood.