Geminiani's first set of concertos had merely been arrangements of violin sonatas by his teacher Corelli. By the time of his Op. 3 collection, though, Geminiani is clearly his own master, although still steeped in the practices of Corelli. Geminiani follows the usual concerto grosso format, with a small solo group, the concertino, playing off the main body of strings with keyboard continuo, the ripieno players. But his figurations, harmonies, and textures are rather eccentric compared to Corelli's smoother models. Furthermore, he takes the unusual step of adding a viola to the concertino ensemble, filling out its texture, but neglects to provide for a viola section in the ripieno group. A 1755 revision corrects this "oversight," but musicians today tend to prefer Geminiani's original version.
In all but the fourth concerto, Geminiani adheres to the standard slow-fast-slow-fast pattern of movements. His part-writing is full and complex for the period, leading some contemporaries, notably Charles Burney, to complain of "confusion" resulting from the busy, dissimilar lines for each instrumental section. Also striking is Geminiani's habit of moving through an unlikely sequence of harmonies along the way to establishing or reestablishing the tonic key. Meanwhile, especially in the fast movements, Geminiani tends to rely on jagged, emphatically repeated little motifs in the manner of Domenico Scarlatti. The music sounded remarkably wild in its time.
Highlights among the six concertos include the virtuosic writing for the solo group, particularly the violin, in the first concerto; the relatively (and unusually) independent viola writing in the last movement of the second concerto; the imaginative contrapuntal material in the fast movements of the third concerto (including a four-part fugue on a chromatic subject); and the dramatic harmonic swings of the second movement of the fifth concerto, ranging through B flat major, C minor, D minor, and even F major along the way to the home key of G minor.