Yes Jamey they do have a "pearly sheen" - similar to that of fiber optic glass sheen - The size is 15mm x 13mm with a 3mm hole.

What is your interpretation of "recent"? And I do not know how to determine type of plastic(s), - plastic smells like plastic - but I cannot differentiate types of plastic. (amber smells like sap)

the red/amber strand of beads measure 12mm x 7mm to 20mm x 16mm - 2.5 - 3mm hole.

I assume they imitate/simulate amber but could not remember their story. I purchased years ago as stated.

Both were purchased through some of my African vendors.
Close up images attached.

Warm Regards,