I have been asked to add a few photos of some older Kokarden to this post, so here they are:
This is an example of the very first Prussian Kokarde to adorn a helmet:
This Kokarde is on a Model 1809 Kurassier helmet. Earlier Kokarden were worn on a tricorn hat. The 75mm Kokarde is made of silk and is colored in standard Prussian colors, black-white-black. Silk is a highly resilient material which can last hundreds of years unless it had been weighted. In the 1840’s manufacturers began weighting silk with sugars and metallic salts to increase profits. It was perfectly legal but the silk material was weakened by it. Weighted silks can dry out, shred, and they do not hold dyes well. Weighted silks also have a tendency to glow under black light, raw silks do not. This Kokarde does not glow under black light.
Here is a pressed wool Kokarde:
This Kokarde is on a Model 1857/60 Fusilier Helmet. The Kokarde appears, at first, to be made of leather, but a closer inspection reveals that it is made of pressed and painted wool. Pressed and painted wool (like heavy felt) was used on models prior to 1857, so this is likely a "left-over" part from an earlier model. It was probably 75mm at one time, but it has shrunk over time.
This is an example of a 75mm stamped metal Kokarde:
This is on a Model 1860 Kugelhelm for the Fuβartillerie. The 75mm stamped metal Kokarde was implemented in 1857 to replace the wool Kokarde.
Here is an unusual 68mm stamped metal Kokarde:
This is on a Model 1853/60 Kürassier Metalhelm. The Kokarde is stamped and seems appropriate in every way --- except size. Prior to 1860 the Kokarde size was 73mm. After 1860 the Kokarde was changed to 63mm. The Kokarde on this helmet measures 68mm --- exactly half way between the two specifications.
This is a 56mm Bremen Kokarde on a Model 1860:
The Kokarde measures 56mm. It is flat instead of convex, which is typical for Bremen, and it has the Hanseatic Maltese cross. The cross is stamped into the Kokarde and not just painted on. The Maltese cross was used by Bremen until 1897 when the Kokarde switched to a white serrated disc with a red ring. The 56mm stamped Kokarde was implemented in 1860 because of the reduced height of the helmet.
John