String sextet

In classical music, a string sextet is a composition written for six string instruments, or a group of six musicians who perform such a composition. Most string sextets have been written for an ensemble consisting of two violins, two violas, and two cellos.
Notable string sextets.
Among the earliest works in this form are the six string sextets Op. 23 of Luigi Boccherini, written in 1776. Other notable string sextets include the Opp. 18 and 36 of Johannes Brahms, the Op. 48 of Antonín Dvořák, the "Souvenir de Florence" (Op. 70) of Pyotr Ilyich Tchaikovsky, "Verklärte Nacht" (Op. 4) by Arnold Schoenberg, the op. 10 of Erich Wolfgang Korngold, Erwin Schulhoff's String Sextet (1924) and the String Sextet (1989) of Charles Wuorinen.
Less usual combinations.
More unusual combinations for a string sextet: