Acronym and details:

Group:   thermoplastic

Developed:   moulding technology from early 17th century

Trade names: 

Manufacturing process:   compression moulding; thermoforming

Cost:   medium

Colour:   natural horn colour, typically dyed black; also imitations of tortoiseshell

Transparency:   translucent or opaque

Rigidity:   rigid but when thin flexes

Feel:   sometimes textured

Smell:   none

Other:   fibrous texture sometimes visible

Typical uses:   drinking vessels; buttons; combs; imitation jet jewellery; snuff boxes; cutlery handles; small translucent panels used e.g. in windows and lanterns

Degradation:   stress cracks; some distortion and shrinkage but otherwise stable