Controlled Chemistry for Fiberglass ActiMin ® FG5. AMI's ActiMin ® FG5 kaolin product is a specially produced airfloated clay for use in the manufacture of eglass type fiberglass used for yarn and reinforcement. Selectively mined and tightly controlled for coarse particles and chemistries, ActiMin ® FG5 product optimizes the customer's melting process and reduces .