COATING (MIRROR BACKING) 
The following report from the 19th Century concerns beads “with a metallic 
appearance:” 
“Sometimes one also sees beads which have a metallic appearance; these are coated on the in- 
side with the amalgama described below and are handled like the larger glass spheres whose 
coating is mentioned later. When the beads are made ofcolored glass, the coating also takes on 
this color. Also betöre the beads are coated, one can line them on the inside with a paint to which 
gum has been added and then the coating done on top of it. Such beads have to be made of 
thickerglass than the waxbeads."(Loysel 1818, p. 309). 
Without going into detail, Keess speaks in 1823 of “metallic composition” for making 
“shiny metallic marcasite or mirror beads” (Keess 2/1823, p. 902). Loth also only 
mentions that “the reflecting beads ...contain a coating of a metal mixture with a low 
melting point." Leng, however, mentions melted tin: 
"... in the shiny metallic marcasite or mirror beads, metallic compositions such as are used for 
silver coating glass balls [are] blown in. If one takes a bead that has just been blown and is still 
hanging on the tube in a glowing state, and holds it in melted tin and draws some of it into the 
tube so that it can be blown back into the bead again, it gets a thin coating inside and shows a 
beautiful play of colors” (Leng 1835, p. 502). 
Pörner also mentions the “mirror” beads colored with tin: 
“After the war of 1866, there was another bead that could be seen here: the so-called mirror 
bead. These beads were lined up on a glass tube during blowing, about 20 beads, 6mm, on the 
one half, the same amounton the other half and in the middle this row of beads was bent, heated 
in the flame and lined with tin and pewter, then heated again and the residue of tin blown out 
again. Finally these beads were strung on threads. These beads were shiny like platinum- 
steel... The beads lined with tin and pewter were completely pushed aside and replaced by the 
silver coated beads” (Pörner n.d., pp. 3, 4). 
As the sources quoted here show, beads with reflecting coatings on their interior walls 
were known at the beginning of the 19th Century as marcasite or mirror beads. The 
beads of a necklace by Anton Schwefel (ill. 230, p. 276) are also labeled as such (in 
the Universal Lexicon by Heinrich Zedier, marcasite is described as “a metall-like 
mineral,“ of which there are “various kinds:” gold, silver, copper, tin or bismuth 
marcasite (Zedier 1739, column 1184). 
The metal mixture used for glass beads consisted, according to Altmütter, of 
“8 parts bismuth, V2 pari lead, the same amount of tin and 9 parts pure quicksilver. The beads are 
blown so that they form a row 4to 5 inches long and between each bead only as much space is 
left as is required for cutting them apart later. Such a row is heated, the lower end placed in the 
liquid metal mixture while one sucks on the top, as a result of which it fills up with the metal. One 
blows the left over metal out again and finally cuts the tubes into individual beads. To protect 
one’s health because of the quicksilver vapors, it would be advisable not to suck with the mouth 
but to accomplish the procedure with the help of a little squirt or pump” (Altmütter 1841, p. 88). 
Beads made from colored, transparent glass tubes (yellow, red, blue or violet) were 
also treated in this manner (Altmütter 1841, p. 88). A number of authors agree in 
naming 1858 as the year in which silver lining by the warm method was introduced 
(Posselt 1907, p. 5; Parkert 1925, p. 140); Arnold places it in the year 1857 (Arnold 
1909, p. 90). Using oil of cloves caused such strong odors that silver coating by the 
cold method (according to the Liebig process) soon took its place (Parkert 1925, 
p. 140). Posselt names Emanuel Fischer in this connection (Posselt 1907, p. 5), while 
Meissner points to Weiskopf who substituted the lead-tin alloy with silver nitrate: 
“It was known for a long time, that when the aldehyde is heated in a tube with silver ammonium 
nitrate, it reduces the silver oxide and the metal precipitates as a shiny coating on the inside of 
the tube ... 6 months ago Drayton’s process became known, according to which mirrorsurfaces 
65