The Holy and Nobel Order of the Knight of Labor was a (proto-)socialist order, spread all over USA in the late 19th century. The order had something like 750 000 initiated members, males and females, whites and blacks, skilled and unskilled workers.* Despite its huge impact on the American worker’s movement, this romantic and mythic socialist order is today, due mainly to the biased historiography of victorious form of socialism, largely forgotten.
The emblems/pins/charms (I am uncertain about the correct term) display the triangle (trinity) of God surrounded by the circle of humanity. If the knights follow the rules of European heraldry, the lozenge-shaped emblems/pins/charms was probably intended for women. The “SOMA” written on one of them is the acronym for the motto of the order: “Secrecy, Obedience, and Mutual Assistance”.
* Best book about the K of L is without doubt Robert E. Weir’s Beyond labor’s veil: the culture of the Knights of Labor. University Park, Pa.: Pennsylvania State University Press(1996). ** From Irons, Charles F. & Charles A. Russell (no year, probably 1895). Illustrated Catalogue of Solid Gold. Society Emblems, Pins, Buttons and Charms. Providence: Irons & Russell, updated version of an earlier version by Irons alone.