My take-away from the above. Comments to refine the below (especially where there are question marks) are appreciated.

Common production methods for cinnabar jewelry pieces after the second quarter of the 20th century:

Second quarter of 20th century-1960s +/-: Cinnabar lacquer made of natural resin applied to a base material, often wood or metal, in thin layers, each layer hardening before the next layer is applied; subsequently carved. Non-toxic pigments used?

1970s-1990s +/-: Synthetic cinnabar resin cast into molds, then carved. In many respects, similar in color and surface appearance to cinnabar lacquer, although lacking layered composition.

1990s-present (?) +/-: Different type of synthetic resin came into widespread use. Brighter red than the above, with a plasticy, shiny appearance. Commonly created in two-part molds, with visible joint marks. Sometimes only roughly formed in molds then carved to completely hide the joints.