The reason you can't see it is because it's coated with a nano material that makes light almost disappear.
你看不见它的原因是因为它被一种纳米材料包裹着,这种材料可以使光几乎消失。
The World From A to Z
The nano material made from the silicone is worth a lot of money.
由硅胶制成的纳米材料价值不菲。
英语百科
Nanomaterials
See the Nanomaterials category for an exhaustive list of articles related to this subject. What follows is an introduction.
Nanomaterials describe, in principle, materials of which a single unit is sized (in at least one dimension) between 1 and 1000 nanometres (10 meter) but is usually 1—100nm (the usual definition of nanoscale).