AVVENTURINA
Avventurina is a type of glass which was invented in Murano around 1620. It presents within its mass countless particles of gold, which are really minute copper crystals - copper is its basic coloring agent. The secret of preparing avventurina, known over the centuries to very few expert glassmasters, is, when the fusion is finished, to add multiple small and successive doses of reducing raw materials such as iron shavings, metallic silicon, or coal, until the metallic copper begins to precipitate. An adequate very slow cooling cycle for the molten glass determines the separation of the metallic copper from the glass base. The quality of the avventurina depends on how homogeneously the copper crystals are distributed and how large the copper crystals, which at best can reach one millimeter in size, are. The origin of the term avventurina is clearly indicated by the XVll th century glassmaster Giovanni Darduin: "it is called venturina, and with reason, because it comes more out of fortune ("ventura") than science."

CRISTALLO / CLEAR GLASS
Cristallo in artistic glass production is transparent glass, homogeneous, absolutely colorless. The secret of quality in cristallo, which is glass, is the purity of the raw materials, the use of bleaching agents, the preparation of the vitrifiable mixture, the fusion process. In the middle of the XVth century Murano invented a pure and colorless glass, which for the first time in history was called cristallo and was later imitated in other European countries. In contrast with Nordic crystal, which has a concentration of lead oxide and today must be subject to strict controls of the fumes deriving from its fusion, its contact with foods and its waste disposal, Murano cristallo is a sodic-calcic glass whose principal components, aside from silica, are sodium oxide and calcium oxide. Murano has always remained faithful to sodic cristallo because it is most suitable for the production of particularly light blown objects which require long working processes.
Opaque colored glass is obtained on the basis of the same principles but with a base of white opaline glass and a larger amount of raw coloring agents.

FENICIO
Also called "graffito" during the past century, it is obtained by wrapping a colored vitreous thread in a spiral around the body of the blown piece, then, near the glory-hole, it is combed with a hooked tool to achieve the characteristic festoons which may also be smoothed into the wall by marvering the piece and blowing it again. This decorative technique dates from the XVIl th century.

FILIGRANA
There are three types of classic filigrana: the "retortoli" type, also called "zanfirico", characterized by subtle twisted white or colored threads inside the thin wall of the blown piece; the "reticello" filigrana, characterized by a fine netting of threads; the "mezza-filigrana" with diagonal threads, an intermediate phase in making "reticello" filigrana. The oldest filigrana is the "retortoli", patented in 1527 by Fililppo Catani, whose furnace bore the sign of the Mermaid (Sirena), the founder of the Muranese Serena dynasty. Ahead of time, the glassworker prepares clear rods with white or colored threads inside wrapped in a spiral. On a slab he positions equal segments of this rod, parallel and adjacent. He then uses his blowpipe to pick up the rectangle obtained by fusing these segments together in the heat, so as to obtain a cylinder which is then smoothed by rolling it over the marver and closed at the end. The piece is subsequently blown and shaped. The "mezza filigrana" is obtained by preparing a rod with a straight thread inside. The glassmaster lays equal and parallel segments of this rod on a slab, fuses it together in the fire and picks up the vitreous rectangle with his blow-pipe. By marvering and closing the resulting cylinder at the end, he twists it to make the threads run diagonally. If two identical glass pieces in mezza-filigrana are prepared with opposite thread patterns and one is blown inside the other, by overlaying the two vitreous walls a grid effect is obtained, the "reticello". Since the surface of the two blown pieces at the moment of their adhesion is still wavy, an air bubble remains imprisoned in each square of the grid, conferring yet another decorative effect.
During the 1950s and 1960s, the Murano glassmaster Archimede Seguso created new types of filigrana, including the "merletto" (lace), using particular procedures for shaping and rods that were previously ground.

INCALMO
Incalmo (the term means "graft") is a technique consisting in joining two blown cylinders, opened to an identical circumference at the edge, along this edge. If the two equal cylinders are of different colors or decorated differently, a single blown piece is obtained with two zones of different colors or decorations. The process may be repeated more than once.

LATTIMO
Lattimo is an opaque white milk-like glass, invented around 1450 on Murano, using a compound of lead and tin as opaquing agents; its purpose was to imitate the first Chinese porcelain to arrive in Venice. During the Renaissance and later in the XVlll th century is was used especially to make refined blown objects to be decorated with polychrome enamels. Today the opaquing agents are tiny crystals of calcium fluoride and sodium which separate from the molten glass during the cooling; the higher the concentration of zinc oxide in the mixture the more homogeneous the glass. Similar to lattimo is enamel glass with a base of lead arsenate , used mostly for making beads and filigrana.

MILLEFIORI
The millefiori rod is a hollow or solid rod composed on the inside of concentric layers of glass in different colors which form, in section, a characteristic star of flower motif. Its production requires a number of open molds which press a star or flower pattern on each successive colored layer, after which the rod is pulled out dozens of meters. A distinct type of millefiori rod is the rosetta, which dates from the XV th century and presents characteristic star motifs in white, red and blue glass in alternate layers. The rod in generally cut into sections, which are often called murrine. If the rod is hollow, the sections may be smoothed and become beads. Solid sections may also be laid side by side and fused in the kiln to make pendants, or on a larger scale, dishes or bowls. The sections of millefiori rod also constitute the modular decorative element, fused to the bottom of a small hemispheric mass of crystal, for paperweights.

ORO / GOLD
In the first phases of hot-work the glassmaster rolls the incandescent glass on the end of the blowpipe over thin leaves of gold or silver which adhere perfectly to the surface. As the glass is blown, the leaves pulverize into gold or silver dust.
The gold leaf may also be applied in decorating workshops on a completely cooled piece. Parts of it may be removed in a decorative pattern, using a sharp instrument. The object must be refired to set the decoration permanently on the glass wall. This technique is generally used together with enamel painting.

SOMMERSO
This technique requires a blown work in thick glass to be immersed in a pot containing transparent glass of a different color and of equal thickness overlaying thick transparent glass to obtain particular chromatic effects.

TESSERAE (GLASS TESSERAE)
A blown piece "a tessere" is obtained by using tesserae in various shapes cut from the surfaces of blown pieces in various colors. The slab fused in the heat is gathered with a blowpipe and shaped into a vessel.