They look like cut German Flints. Not sure why RMC would sell them. They have never been as good as English flints for L&R locks which is what are used in RMC's rifles. However, a quick search on RMC's web site did not show any rifle sized flints except the Jaspis. (Musket flints yes) I am always willing to learn about something better, but 40 years of muzzle loading and I have never heard of cut flints being as good on custom locks as English, or amber or chert.