Familia Romana Cap VIII - Ablativus pretii

FR Cap VIII section II

Tanta gemma sola octoginta sestertii constat = Ablativus pretii, plural, on account of “constat”.

Pretium huius anuli est centum sestertii = Ablativus pretii because of the implied “constat”, but not sure. Could the “est” mean centum sestertii is in fact a “complement”?

Where do you think the ablative is in this sentence?

Gratias tibi ago, seneca.

Had to move this to a new “reply”.

Gratias tibi ago, seneca.

I now see what happened: Tanta gemma sola octoginta sestertii constat. “sestertii” should have been “sestertiis” (Ablative). Having fixed on my typo “sestertii” I conveniently overlooked that we were no longer in Ablative mode.
I hope I got that right.
What a difference an “s” makes! Sorry, more haste, less speed :blush: