Cortex is a light pinkish-peach hue. It is mostly opaque, with a slight translucency to enhance its fleshy quality. These colors can be easy to boil, so bring them up to temp gradually in the back of a soft flame. They can be mixed with clear or encased to make them easier to use.
All of the RealTones are meant to be WYSIWYG and mixable with each other as well. You can achieve a wide variety of colors by hand or drill mixing these together. They smooth out nicely when coil-potting, leaving minimal witness lines.