These special acorn caps are placed into a colorful mix of swirling Alumilite resins. Once turned down these will give your pen a beautiful and unique appearance. A real conversation starter! The acorn caps can have some voids in them as it is nearly impossible to get the resin to penetrate completely through. If this does happen, we suggest a filling any gaps with a color matched epoxy or CA. A top finish (like CA) is also recommended for these blanks. This unique formulation of acrylic to emulate various marble and granite textures. Your turned pens will have an elegant architectural look.