Silicone is sand. Look for a failed air filter. Also, are any silicone sealants used on the engine?
Think of any thing made with silicon that might be in contact with the engine oil or the intake air.
I think Silicone and Silicon are two different things. But I'm not a chemist, and I didn't sleep at any Motel or Hotel last night!!
You sure it wasn't Silicon in the oil analysis? As mentioned above, Silicon is usually "dirt". Sand, dust, etc.
Has anyone ever torn down or overhauled their engine based on an oil analysis? (you know where I'm going with this).