Gem and Ornamental

Figure 2.9Vulcanite chain linlc which hag not been cut through.&is dufci is often mentioned as ti simulmt for jet but was in factseldom used because it was formed in large, steel moulds, whichwere not suitable for the production of amdl items. It was a mixtureof hardwood flour and ox blood, coloured with lampblack (a formof soot). It took a good, detailed imprint, was durable, and had itsown niche, being used for plaqua, barometer -8, dwells andother luge. items (Fii. 13.2). The mat4 gives a brown streak,but the words 'Bois Durci' often appear moulded into the back orbottom of an object.Shellac was a substance excreted by insects. It was mixed withwood flour, moulded and dyed - usually black or brown. It waslighter than bois durci and eve good detail in moulding. It wasused to make picture frames (Fig. 13. l), dressing table sets, somejdery and, notably, 78 rpm gramophone records. Bxaminedunder a microscope it is possible to see the wood content. Blackshellac gives a black streak.Celluloid was one of the early plastics that was used in numerousways. It was made of cellulose nimte and was -elycombustible, but a saCer version, cellulose acemte, was later developed.Dyed black, they are reasonable imimtions of jet but hey havea plasticy look and feel. Black celluloid gives a faint, black meakBakelite, or phenol formaldehyde, could be dyed any colour andwas widely ud. When dyed black it was also a reasonable jetimitation, but it dulls with age and has a plasti* look and feel.Black Bakelite gives a black M