Cluthra: Steuben's Bubble-Textured Art Glass
Cluthra is a type of art glass developed by Frederick Carder at the Steuben Glass Works in Corning, New York, around 1920. The name derives from the Scottish word "cluthar" (meaning clouded), and the glass is characterized by a distinctive bubbly, mottled texture created by trapping air bubbles and colored glass fragments within a thick casing of crystal. Cluthra glass appears in a range of colors including white, green, pink, blue, and amethyst, and represents one of the most recognizable of Carder's many innovative glass formulas.
History and Production
- Frederick Carder (1863-1963) founded Steuben Glass Works in 1903 and developed Cluthra around 1920
- The technique involves rolling the gather of molten glass over crushed glass fragments and powdered chemicals, then encasing the result in clear or colored crystal
- The trapped fragments and chemicals create gas bubbles during subsequent firings, producing the characteristic mottled, bubbly interior
- Production continued through the late 1920s and into the 1930s, when Corning Glass Works reorganized Steuben under Arthur Amory Houghton Jr.
- Kimble Glass Company also produced a similar line called "Clutha" (not to be confused with Steuben Cluthra)
Identification
- Texture: Genuine Cluthra has randomly distributed bubbles and color variations throughout the glass body; no two pieces are identical
- Weight: Cluthra pieces are typically heavy due to the thick glass walls required by the process
- Marks: Many pieces bear an acid-etched "Steuben" fleur-de-lis mark on the base; some unmarked examples exist
- Colors: Most common in white, green, and pink; blue, amethyst, and multi-colored examples are rarer
- Forms: Vases (the most common form), bowls, plates, and occasional lamp shades
Auction Price Ranges
| Color/Form | Description | Price Range |
|---|---|---|
| Large vase, rare color | Blue or amethyst, 10+ inches | $3,000 - $10,000 |
| Large vase, common color | White or green, 10+ inches | $1,000 - $4,000 |
| Medium vase | Any color, 6-9 inches | $500 - $2,000 |
| Small vase | Any color, under 6 inches | $200 - $800 |
| Bowl | Any color | $300 - $1,200 |
| Multi-colored example | Two or more colors blended | $1,500 - $5,000 |
| Lamp shade | Cluthra glass | $400 - $1,500 |
Condition Factors
- Surface scratches: Cluthra's textured surface can mask minor scratches, but deep scratches or chips are clearly visible and reduce value
- Bubble distribution: Evenly distributed, well-developed bubbles are preferred; thin areas with few bubbles suggest a production deficiency
- Color saturation: Strong, vibrant color throughout the piece is more desirable than pale or uneven coloration
- Grinding: Check the base for grinding marks that are consistent with Steuben's production methods; rough or amateur grinding may indicate an attribution problem
- Cracks: Internal stress cracks can develop in thick-walled Cluthra glass; hold pieces up to light to inspect
Collecting Tips
- Color drives value -- blue and amethyst Cluthra are the scarcest and command the highest prices; white and green are more available
- Steuben marks (acid-etched fleur-de-lis) confirm attribution but are absent on some genuine pieces; unmarked examples should be evaluated on form and quality
- Do not confuse Steuben Cluthra with James Couper & Sons' "Clutha" glass (designed by Christopher Dresser in the 1880s), which is an entirely different product
- Pair Cluthra with other Carder-era Steuben lines (Aurene, Cintra, Intarsia) for a comprehensive collection of his innovative glass techniques
- Large-scale pieces (over 12 inches) are rare and bring disproportionate premiums
- Handle carefully -- the thick walls make Cluthra heavy, and drops result in catastrophic shattering rather than simple chips