This little collar is a great example of crocheting over a core thread or padding, which was a common technique in Irish Crochet. What you do, is wind thread around your finger or something similar. Then you make as many single-crochets as possible over the resulting thread ring.
The rings in this collar are plump, which means the crocheter made many rounds with the padding thread before starting to crochet. They are satiny, which means there are lots and lots of single crochets. The criss-cross threads in the center of some rings are done with a needle and thread. I can’t tell whether they stabilize the ring or whether they are simply another detail in the design.
The skinny threads and the plump rings and the medium-weight of the crochet make this piece very intriguing to the eye. The collar is damaged around the inside edge, but I mainly wanted it to illustrate padded crochet. Collecting is so much easier if you aren’t a perfectionist.