Built in 1927 on the site where the old state capitol had burned in 1921, Charleston's grand Diamond department store was among West Virginia's flagship retail establishments. Designed by architect Charles Haviland, the original building was a state-of-the-art store. Its five floors featured daylight lighting, arcade display windows, modern ventilation, three fast elevators, and a pneumatic tube system to convey cash and receipts between sales stations and the central office. The 1927 building was improved and expanded in later years.

Merchants Wehrle B. Geary and A. W. Cox had merged their resources in 1926 to launch the elegant new store at the edge of Charleston's business district, on Capitol Street near its intersection with Washington. The name originated with Geary. He had opened the Diamond Shoe Store in 1906. This became the Diamond Shoe and Garment Co. in 1912 and reached full department store status in 1917, moving farther up Capitol Street each time. In the meantime, Cox was assembling his chain of retail stores.

Successful even during the Depression, the partners expanded to the corner in 1941 when an extension was added to the original building featuring two air-conditioned floors and a basement. In 1948 five floors were added to the 1941 addition, bringing this part of the store to a full seven stories. Ten escalators, West Virginia's first, were installed.

Renowned for personal service, the Diamond in its heyday offered portraits by photographers as well as an on-site artist; a discreet wig booth within its beauty salon for patrons with thinning hair; a book store with author signings and luncheons; and store-to-church bridal assistance. Hungry shoppers flocked to the luncheonette on the first floor and the large cafeteria on the fifth. Mechanized toylands, trains, and nativity scenes drew crowds to its street corner window during the holidays. Peak December days brought as many as 80,000 shoppers into the glamorously decorated emporium.

The Diamond, however, barred African-Americans from its lunch counter and cafeteria for decades. African-American organizations waged a two-year boycott of the store, and students from West Virginia State College (now University) staged a sit-down protest at the lunch counter. The department store finally integrated its dining facilities on May 3, 1960.

Associated Dry Goods bought the Diamond in 1956, built a $1 million addition eastward in 1965, and prospered until the completion of the Town Center Mall in 1983. The Diamond inventory was liquidated and the business closed in that year. The building, still a Charleston landmark, has been refurbished for use as state government offices.