This rare official stamp from South Australia, issued on February 18, 1874, represents the 2 pence value printed in orange-red with the distinctive "O.S." overprint (Type I), designating its use exclusively for official government correspondence. The stamp belongs to the definitive series portraying Queen Victoria, engraved with fine detail emphasizing the diadem and formal profile, a design reflecting the authority and prestige of the colonial postal service. Printed by typography and perforated 10, it carries the watermark Crown over SA, Type 2 (upright). Official stamps such as this were vital in differentiating governmental from private use and remain highly collectible due to their limited circulation compared to standard issues. Comparable examples have appeared in notable Australian philatelic auctions, where condition and clarity of the overprint significantly influence demand. Catalogued as Michel AU-SA D8 and Stanley Gibbons AU-SA O38, it holds a firm place among the important issues of the late 19th century colonial period, when South Australia was asserting administrative independence prior to Federation.
Condition: Used example with clear cancellation and legible overprint; trimmed margin and light wear consistent with postal use.