The following is a picture of silicon in nature
There are various types of silicone oil, from watery to syrupy ones.
The photo is silicone oil with high viscosity. Silicone oil is excellent in transparency.
There are some from powder to solid type as shown in the photograph.
Transparent silicone rubber (liquid rubber)
It is transparent like water and shines brightly when hit with light.
It is silicone rubber for molding. You can reproduce the prototype exactly.