Abstract. Let F (x, y) ∈ Z[x, y] be a quadratic form such that the associated algebraic curve C : F (x, y) = 1 contains a rational point. Here we show that there exists a domain D ⊆ R such that for almost all ξ ∈ D, there exists an infinite sequence of nonzero integer triples (x n , y n , z n ) satisfying the following two properties: (i ) For each n, x n /y n is an excellent rational approximation to ξ, in the sense that limand (ii ) (x n /z n , y n /z n ) is a rational point on the curve C. In addition, we give explicit values of ξ for which both (i ) and (ii ) hold, and produce a similar result for a certain class of cubic curves.