What does vermiculite insulation look like? From a distance, vermiculite looks like small pebbles or gravel. Vermiculite is usually a brownish-gray or silver-gold color, but the color will fade to gray over time. Vermiculite is made up of minerals extracted from the ground and which, when heated to a very high temperature, explode to expand like a grain of corn being heated. Therefore, vermiculite is a very light material and that is why it was very easy to apply in attics.