Material · 7 min read
Dating buttons — bakelite, casein, celluloid, jet
Plastic buttons, glass, mother-of-pearl, jet, bone. Each material has a dating window and a simple identification test.
Buttons are a secondary dating clue but a useful one. The major button materials — bakelite, casein, celluloid, jet, mother-of-pearl — each have date windows and can be identified with simple tests. Original buttons in a garment from a specific era reinforce the dating from other clues; replaced buttons often expose a piece that has been heavily altered.
Material by date
| Material | Active dates | Identification |
|---|---|---|
| Bone, horn, wood | Pre-1900 onward | Natural, organic feel; bone often has tiny dark canals visible at the surface. |
| Jet (compressed coal) | 1860–1900 (Victorian mourning), revival 1920s | Black, lightweight, warm to touch. Distinct from black glass. Genuine jet is rubbed with a cloth to produce static. |
| French jet (black glass) | 1880s–1920s | Heavier than jet, cold to touch. Often confused with jet by amateurs. |
| Mother-of-pearl | All eras | Iridescent natural shell. Cool to touch. Distinguishable from plastic imitations by the natural irregular sheen. |
| Celluloid | 1869 onward, peak 1900–1940 | Early plastic. Lightweight, smells of camphor if rubbed warm. Highly flammable. Often colour-imitated bone or tortoiseshell. |
| Bakelite | 1907–1940s | Phenol-formaldehyde plastic. Heavy, warm-to-touch, smells of formaldehyde when warmed. Tested with Simichrome polish (yellow stain on a cotton swab indicates bakelite). |
| Casein (milk plastic) | 1900–1940s | Made from casein protein. Lighter than bakelite. Often used to imitate mother-of-pearl or horn. |
| Lucite / acrylic | 1937 onward | Clear or coloured acrylic. Light, often transparent. Common 1940s–1960s on novelty buttons. |
| Polyester / nylon plastic | 1960s onward | Modern injection-moulded plastic. Light, uniform, no characteristic smell. |
The bakelite tests
Bakelite is the most collectible vintage plastic and the most often faked. Two reliable home tests:
- Simichrome polish test: Apply a small dab of Simichrome to a cotton swab and rub gently on the button back. Genuine bakelite turns the swab bright yellow. Lucite, casein, and modern plastics do not. This is the gold-standard test.
- Hot water test: Run the button under hot water for thirty seconds, then smell. Bakelite has a distinctive formaldehyde or burning-wood smell. Casein smells faintly of burnt milk. Modern plastics have no smell.
- Weight: Bakelite is significantly heavier than later plastics. A bakelite button feels denser than a same-size acrylic button.
Never use Formula 409 or bleach as a bakelite test, despite what older guides suggest. Both damage the surface and can permanently mark genuine pieces.
Jet vs French jet
Genuine jet (compressed Cretaceous coal from Whitby, Yorkshire) was the dominant Victorian mourning button material from about 1860 to 1900. French jet, which is black glass, replaced it in cheaper production from the 1880s onward. The distinction matters for value: genuine Victorian jet buttons command real prices; French jet is more abundant.
- Genuine jet: warm to touch (organic material), lightweight, produces static when rubbed against wool, may have small natural inclusions.
- French jet (glass): cold to touch, heavier than jet, does not produce static, uniform surface with characteristic glass shine.
Original vs replaced buttons
Replaced buttons are common — buttons are the most often lost or damaged element of an old garment. Look at the thread, the button shank, the spacing, and the hole positions. Original buttons typically have consistent thread that matches the lining or interior. Replaced buttons often show fresher thread, different colour, or visible new stitching against aged fabric. A piece with all original buttons holds materially more value than the same piece with replaced buttons.
Frequently asked
Does replacing buttons reduce the value of a vintage garment?
Yes — and the magnitude depends on the piece. For a 1950s housedress, replacement buttons might reduce value by 10–20%. For a 1930s Schiaparelli with surrealist novelty buttons, replacement reduces value substantially because the buttons were a defining feature of the original design. Always retain original buttons in a labelled envelope if you must replace for wearability.
Are bakelite buttons safe to wear?
Yes. The phenol-formaldehyde polymerisation is complete; the material is stable. Avoid prolonged exposure to high heat (an iron directly on the button will damage it) and aggressive solvents.
How do I tell mother-of-pearl from plastic imitations?
Mother-of-pearl has natural irregular iridescence — the rainbow sheen shifts and varies across the surface. Plastic imitations have uniform iridescence that looks too perfect under light. Mother-of-pearl is cool to touch; plastic warms quickly to body temperature. Under magnification, real shell shows fine layered structure; plastic appears smooth or uniformly stippled.
By Margaret Hale·Published 18 May 2026·Last reviewed 18 May 2026