Two Ancient Techniques of Making a Crystal Vase

The earliest records uncovered that detail the ancient pate de cristal technique of constructing exquisite crystal vases date all the way back to the Mesopotamians of second millennium B.C. Their decorating and jewelry-inlay techniques inform a style still admired to this day.
1. At the start of the process, each potential masterpiece begins as clay or wax model sculpture in the desired shape the vase will take in its final form. (In the days of the Mesopotamians, this was instead a bag of sand or dung.)
2. Then the wax is covered with a mold of plaster or rubber in order to create a replica of the original sculpture. (For the less technologically advanced Mesopotamians, this meant covering the filled bag with threads of glass in its liquid form.)
3. After the plaster dries, the wax is steamed until it melts out of the plaster, leaving an empty mold. (For the Mesopotamians, this meant scraping out the bag once the glass dried.)
4. The remaining plaster is then filled with colorful powdered glass as paint, then heated inside a kiln and allowed to cool until it reaches room temperature. (For the Mesopotamians, this meant filling the mold with impure sands in order to bring color to their creations - iron for light greens, magnesium for pinks or violets, sulfur for yellows and dark greens, and silver-free sand or antimony for colorless glass.)
5. At room temperature, the vase is removed from the mold, relieved of any stray glass on its surface, smoothed of any rough edges, the either polished with abrasive materials for the highest possible sparkle or sandblasted for a more frosted or etched decor, and finally ready to showcase.
The Romans, however, introduced a less tediously challenging, and more modern technique, called glassblowing, more frequently employed by makers of today's vases. Their technique emerged as a way of developing more sophisticated and ornate crystal and glass vases ranging from clear glass to colored crystal, decorated by enameling, gliding, or staining techniques. Vases of pure crystal first emerged late in the 15th century, created by Italian glassblowers in Murano who had perfected and protected the technique adopted from the Romans.
1. First, the purest sources of silica (the base ingredient of glass) are selected, and scrutinized to avoid mineral impurities, veins, and discolorations, as well as to ensure that they will spark once struck with steel. The Murano's material of choice was called cogoli, naturally occurring pure silica found within quartz pebbles in abundance on their river beds.
2. The chosen pebbles are heated until they glow, and then dipped in cold water to remove any remaining impurities from within the material.
3. Next, the pebbles are ground into the finest powder possible to ensure the beauty of the final product.
4. Next, a fluxing agent is used to lower the glass's melting point, for melting in a clay wood-burning oven, and then also added to the enamels that will later be used to apply decoration. The Murano's agent of choice was a mixture for which they possessed the sole trade monopoly - created by burning Salsola soda and Salsola kali plants from the Levantine region, then sifting their particles until only the smallest remained, boiling them repeatedly to release its salts, then allowing them to air dry in order to recrystallize as white salt to be powdered yet again with the focus of removing excess iron that could discolor the glass of the final product.
5. Then Magnesium is added to the mixture in order to further inhibit discoloration that could result from iron or other impurities, as well as to lengthen the time of glass's malleability during the design stage.
6. Then, glass-makers form a glass batch by framing the glass, then having it blown, twisted, and cut in their desired vase or other shapes by able hands. The thinner the glass batch, the less visible any impurities are - but also the more delicate to shape further without breaking or misshaping it.