The best test is to run the piece under hot tap water, or wear the bangle while you relax in the hot tub or shower. If it smells a little like your old high school chemistry lab (formaldehyde), it's Bakelite. If it smells like vicks vapo-rub (camphor), it's Celluloid. If it smells like burnt milk, it's Galalith (1920's). If it smells clean, or like nothing at all, it's lucite or acrylic. In any marbled piece, there should be vertical lines on the inside of the bangle.
Creme: Creamy white
Creamed Corn: Light creamy yellow
Custard: The color of egg custard
Butterscotch: Golden yellow with a hint of brown
Toffee: Light yellowish brown
Golden: Medium golden greenish brown
Cocoa: Light brown
Chocolate: Medium brown
Coffee bean: Dark brown
Rootbeer: Transparent golden brown, often with black swirls
Black: True black, no other body color when held to light
Apple juice: Transparent golden yellow
Pineapple: Light yellow
Lemon: Intense bright yellow
Tangerine: Intense bright orange with a hint of yellow
Coral: Pinkish orange
Melon: Cantaloupe orange
Rust: Deep orange with a hint of brown
Peppermint: Light pink
Fuscia: Strong Deep Pink with a hint of blue
Cherry: Intense bright red
Tomato: Red with a hint of orange
Rasberry: Red with a hint of blue or purple
Cranberry: Purplish red
Wine: Deep burgundy red
Navy: Dark navy blue
Vaseline: Yellowish green, the color of Anti-freeze
Chartreuse: Light celery green
Lime: Intense bright green
Green apple juice : Transparent bright green
Olive: Olive green
Moss: Deep brownish green
Forest: Deep green
Leaf : Medium green with a hint of blue
Pea soup: Medium green with a hint of brown
Jade: Mottled medium and darker greens
Creamed Spinach: Greens swirled with white or yellow
Ink spot: Dark bluish green splotches on yellow backround
Teal: Dark greenish blue
Blue moon: Dark teal with yellow marbling
End of Day: A mixture of three or more colors, supposedly created at the end of the day, when all the remaining plastic from the day's production were combined.
DESCRIPTION OF PLASTIC
Plain: Uniform color throughout.
Marbled: A blended swirl of two or more colors.
Layered: One color of plastic on top of another with indistinct boundaries between the colors.
Laminated: One color of plastic on top of another with distinct boundaries between the layers.
Transparent: Transparent, and appears transparent when worn.
Light Transparent: Plastic that appears translucent, but is actually transparent when held to the light.
Translucent: Like holding a piece of bone china up to the light, and discerning the shape of your fingers through it. In some marbled plastics, there may be a mixture of transparent and translucent areas.
Opaque: Light does not pass through the plastic, or does so only on thinner areas, such as in the valleys of the carved areas or along the edges.
Light weight: Light weight and thin.
Medium weight: Medium weight and average thickness.
Chunky weight: A heavier more substantial weight piece.
Heavy weight: A bold heavy piece, sometimes reaching as much as an inch or more in thickness at it's thickest point.
Domed: A domed piece is thicker in the center and tapers at the edges.
Sliced: A sliced bracelet is the same thickness throughout, without tapering at the edges.
Etched: Very faintly carved surface decoration
Lightly Carved: Faint carving
Medium Carved: Average depth carving
Deeply Carved: Deeper than average carving
Heavily Carved: Extremely deeply carved
Faceted: Carved with a regular pattern of facets
Grooved: Routed out in a line
Pierced: The material has been cut completely through
Inlaid: A space is routed out of the material, and a contrasting material is fitted into that space. Bakelite polka dot bracelets are an excellent example of inlay technique.
lots from http://www.plasticfantastic.com/glossary.html