Silicone usually has a 'sheen' to it and it feels 'slick'. The caulking around your tub/shower is most likely silicone and makes a goods reference. The Dicor/rubber caulking will look 'dull'.. more like concrete crack filler in sidewalks..
Heres a good example: The 'dull grey' sealer around the vent pipe is a Dicor type.. The white 'shiny' stuff on the cable is silicone...