Bazin, X., 3¢ green, essay plate proof on card (Scott RT1 var.), nice margins and color. Unlisted in Scott. Turner notes the 1¢ and 3¢ values were never issued, so these must be considered essays.
Xavier Bazin established a soap and perfumery business in Philadelphia sometime before 1850. He manufactured X. Bazin’s Celebrated Toilet Soaps, Shaving Creams, Bandoline, Philocome Pomade, Toilet Waters, Cosmetics, Bulk Extracts, Cologne, etc. He was the sole proprietor until the mid 1870s when his sons joined the business. In 1875, he formed a partnership with Robert O. Kilduffe, forming X. Bazin & Co. In 1877, Hall and Ruckel of New York became sole agents for his products.
X. Bazin was one of the first firms to order private die proprietary stamps, October 2, 1862 according to Butler & Carpenter, also of Philadelphia. For an undetermined reason, X. Bazin never followed through with ordering stamps, and the entire printing were to be destroyed in 1867. However, copies of the two-cent blue are known. 81,360 of these were printed, all on old paper, and some apparently escaped destruction.
In addition, die and plate proofs of the 1c, 2c, and 3c stamps exist. Since the 1c and 3c stamps no longer exist, their proofs technically are regarded as essays.