The following is a picture of silicon in nature
Silicone oil
There are various types of silicone oil, from watery to syrupy ones.
Silicone oil
The photo is silicone oil with high viscosity. Silicone oil is excellent in transparency.
Silicone range
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.
RTV rubber
It is silicone rubber for molding. You can reproduce the prototype exactly.