This Thumbprint bracelet may be by silver master Antonio Pineda. It is a variation of his traditional all silver Thumb bprint bracelet. I have not seen one like this in which the silver links alternate with onyx.
The ambiguity has to do with the mark. The circular mark under the clasp looks as though it is one that often accompanies Antonio's crown but I cannot say with 100% certainty.The tall push clasp with a wide circle is certainly one used by Antonio.
Regardless of whether it is by Antonio or not, it is a substantial, very well made and probably original piece. It weighs 147 grams. It is 9 plus inches long (difficult to be precise because of the safety chain) and 1" wide.