Let
\mathbb F be a finite field of odd order and
a,b\in\mathbb F\setminus\{0,1\} be such that
\chi(a) = \chi(b) and
\chi(1-a)=\chi(1-b), where χ is the extended quadratic character on
\mathbb F. Let
Q_{a,b} be the quasigroup over
\mathbb F defined by
(x,y)\mapsto x+a(y-x) if
\chi(y-x) \geqslant 0, and
(x,y)\mapsto x+b(y-x) if
\chi(y-x) = -1. We show that
Q_{a,b} \cong Q_{c,d} if and only if
\{a,b\}= \{\alpha(c),\alpha(d)\} for some
\alpha\in \operatorname{Aut}(\mathbb F). We also characterize
\operatorname{Aut}(Q_{a,b}) and exhibit further properties, including establishing when
Q_{a,b} is a Steiner quasigroup or is commutative, entropic, left or right distributive, flexible or semisymmetric. In proving our results, we also characterize the minimal subquasigroups of
Q_{a,b}.