Lead glass in the context of Amorphous solid

Lead(II) oxide, also called lead monoxide, is the inorganic compound with the molecular formula PbO. It occurs in two polymorphs: litharge having a tetragonal crystal structure, and massicot having an orthorhombic crystal structure. Modern applications for PbO are mostly in lead-based industrial glass and industrial ceramics, including computer components.

Fused quartz, fused silica or quartz glass is a glass consisting of almost pure silica (silicon dioxide, SiO₂) in amorphous (non-crystalline) form. This differs from all other commercial glasses, such as soda–lime glass, lead glass, or borosilicate glass, in which other ingredients are added which change the glasses' optical and physical properties, such as lowering the melt temperature, the spectral transmission range, or the mechanical strength. Fused quartz, therefore, has high working and melting temperatures, making it difficult to form and less desirable for most common applications, but is much stronger, more chemically resistant, and exhibits lower thermal expansion, making it more suitable for many specialized uses such as lighting and scientific applications.

The terms fused quartz and fused silica are used interchangeably but can refer to different manufacturing techniques, resulting in different trace impurities. However fused quartz, being in the glassy state, has quite different physical properties compared to crystalline quartz despite being made of the same substance. Due to its physical properties it finds specialty uses in semiconductor fabrication and laboratory equipment, for instance.

Cut glass or cut-glass is a technique and a style of decorating glass. For some time the style has often been produced by other techniques such as the use of moulding, but the original technique of cutting glass on an abrasive wheel is still used in luxury products. On glassware vessels, the style typically consists of furrowed faces at angles to each other in complicated patterns, while for lighting fixtures, the style consists of flat or curved facets on small hanging pieces, often all over. Historically, cut glass was shaped using "coldwork" techniques of grinding or drilling, applied as a secondary stage to a piece of glass made by conventional processes such as glassblowing.

Today, the glass is often mostly or entirely shaped in the initial process by using a mould (pressed glass), or imitated in clear plastic. Traditional hand-cutting continues, but gives a much more expensive product. Lead glass has long been misleadingly called "crystal" by the industry, evoking the glamour and expense of rock crystal, or carved transparent quartz, and most manufacturers now describe their product as cut crystal glass.

Waterford Crystal is an Irish manufacturer of crystal glassware, especially cut glass products. It is named after the city of Waterford in Ireland. In January 2009, the main Waterford Crystal manufacturing base on the edge of Waterford was closed due to the insolvency of Waterford Wedgwood plc, and in June 2010, Waterford Crystal relocated almost back to the roots of glass-making in the city centre. The Mall location holds both a manufacturing facility that melts over 750 tonnes of crystal a year – although most Waterford Crystal is now produced outside Ireland – and a visitor centre with the world's largest collection of Waterford Crystal. Since 2015, the brand has been owned by Fiskars Corporation.

Daum is a crystal studio based in Nancy, France, founded in 1878 by Jean Daum (1825–1885). His sons, Auguste Daum (1853–1909) and Antonin Daum (1864–1931), oversaw its growth during the burgeoning Art Nouveau period. Daum is one of the only crystal manufacturers to employ the pâte de verre (glass paste) process for art glass and crystal sculptures, a technique in which crushed glass is packed into a refractory mould and then fused in a kiln.

Flint glass is optical glass that has relatively high refractive index and low Abbe number (high dispersion). Flint glasses are arbitrarily defined as having an Abbe number of 50 to 55 or less. The currently known flint glasses have refractive indices ranging between 1.45 and 2.00.

Traditionally, flint glasses were lead glasses containing around 4–60% lead(II) oxide; however, the manufacture and disposal of these glasses were sources of pollution.