Rookwood Pottery Marks: How to Read the Flame, RP, and Artist Monograms
Rookwood Pottery of Cincinnati, Ohio operated from 1880 to 1967 and produced some of the finest American art pottery ever made. Their pieces — particularly artist-decorated standard glaze, iris glaze, and vellum glaze examples — sell from $200 to over $100,000 depending on the artist and subject. The marking system is among the most systematic of any American pottery: the reverse flame mark allows you to date a piece to the exact year, and artist monograms identify the individual who decorated it.
The Flame Mark System: Exact Year Dating
The primary Rookwood mark is the 'RP' monogram (R and P combined, often called the 'reverse RP') with a flame added above it for each year after 1886. One flame = 1887; two flames = 1888; three = 1889, and so on. Fourteen flames (1900) is the maximum — from 1901 onward, Roman numerals replace the flames. 'I' under the RP mark = 1901; 'II' = 1902; and so on through 1967. This system allows exact year dating from the base mark alone. Additional marks appear alongside: a shape number (identifies the form), a size letter, a clay body indicator (Y for yellow, R for red, S for sage, G for ginger), and a glaze designation.
Artist Monograms: Identifying the Decorator
Rookwood employed dozens of artists, and the most famous command significant premiums: Matthew Daly (MD), Kataro Shirayamadani (K with a Japanese character, or a stylized 'K'), John Hamilton (JH), Carl Schmidt (CS), Sara Sax (S with a small 'x'), and Harriet Wilcox (HEW). Monograms appear incised or painted on the base. Published Rookwood monogram guides (available online) identify every documented artist. An unsigned Rookwood piece is worth 30–50% less than a signed example in equivalent glaze and condition. Shirayamadani-signed pieces with naturalistic Japanese-influenced decoration consistently achieve the highest prices — $5,000–$50,000+ at major auctions.
Glaze Types and Their Value Hierarchy
Standard Glaze (dark amber-to-brown ground with slip-painted decoration): the most common Rookwood glaze, produced 1884–1909. Iris Glaze (clear to white ground showing lighter, more delicate decoration): rarer, 1894–1912, generally 2–3× Standard Glaze values. Vellum Glaze (matte, translucent ground used for landscape and scenic pieces): 1904–1948, particularly valued for exceptional scenic examples. Sea Green Glaze (blue-green tinted ground): 1894–1904, relatively rare and valuable. Matte Glaze (post-1905): various solid-color matte finishes — lower value than earlier decorated glazes but desirable in exceptional painted examples. The combination of glaze type + artist + subject + condition determines final value.
Condition and Grading Standards
Mint (M): no chips, no cracks, no restoration, all glaze intact — maximum value. Excellent (E): very minor glaze crazing on pre-1910 pieces (acceptable), no chips. Good (G): base chip only, no cracks. Fair (F): visible chip on body or rim, professional repair present. The 'grinding' of the impressed mark (sometimes done to pieces with factory defects that were sold as seconds) reduces value significantly — a 'X' or other defect marking on the base indicates the piece left the factory as a second-quality item. Hairline cracks visible under UV light reduce value 30–60% depending on location.
On-Site Identification Steps
Count the flames above the RP mark to determine year (one flame = 1887; for post-1900, read the Roman numeral). Note the shape number for later form identification. Look for the artist monogram — photograph it for research. Identify the glaze type: dark brown ground = Standard, light/clear ground = Iris, matte translucent = Vellum. Check for the defect 'X' mark. Examine condition under a UV light if available — repairs and hairlines fluoresce. Cross-reference the shape number and artist against published Rookwood references (the Cincinnati Art Museum maintains extensive Rookwood records online). These steps take 3–5 minutes and provide enough data for accurate pre-purchase research.
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