Hand-Blown Convex Glass Silvering & Diamond Scribing Craft

In the royal workshops of Jaipur and Amber, the creation of thikri began with the fiery craft of the traditional glassmaker (sheeshgar). Unlike European mirror manufacturing, which sought flat, flawless plate glass for functional grooming mirrors, Rajasthani architectural inlay was conceived entirely around curved, spherical glass. Operating small wood-fired clay furnaces fueled by seasoned babool wood, master glassmakers melted batches of indigenous silica sand, soda ash (sajji), and slaked lime at temperatures exceeding 1350°C.

Gathering a small gather of molten glass on a narrow iron blowpipe, the artisan rolled the gather on an oiled iron marver before blowing a hollow glass sphere known as a haddi. The glassblower's skill was judged by dimensional consistency: the sphere—measuring between 150 and 200 millimeters in diameter—had to maintain a uniform, feather-light wall thickness between 0.8 and 1.2 millimeters. If the glass was too thick, it was impossible to cut into intricate floral shapes; if too thin, it shattered under the pressure of the diamond cutting stylus.

While the blown glass globe remained warm from the furnace, the interior surface underwent the magical transformation into a mirror. In early Mughal and Rajput workshops, this was accomplished through molten metal amalgamation. A low-melting-point alloy composed of refined tin, lead, and zinc—often modified with a trace of purified metallic mercury—was melted in a ceramic crucible and poured into the neck of the globe.

Holding the sphere with thick leather rags, the master artisan swirled the molten metal rapidly in continuous multi-axis rotations. As the liquid metal contacted the smooth inner glass wall, it formed a continuous, molecular bond, creating a soft, warm, silvery-pewter mirror. In the eighteenth and nineteenth centuries, this pyrotechnic method was refined through wet chemical reduction: an aqueous solution of silver nitrate (AgNO3) was dissolved with ammonia and poured into the globe along with Rochelle salt (potassium sodium tartrate) or invert sugar. Within four minutes, metallic silver precipitated out of solution, plating the inner glass with a microscopically thin, brilliant film of pure specular silver.

Once the silver film had cured and was protected with an internal coat of alcohol-dissolved shellac or natural asphaltum varnish, the sphere was ready to be harvested. Striking the brittle glass neck with a copper rod, the artisan caused the entire hollow sphere to fracture into dozens of curved, triangular and polygonal shards known as thikri.

These shards were sorted with extreme care. The curvature of the sphere varies slightly from the equator to the poles: equatorial shards have a flatter, sweeping curve ideal for broad background wall fields, while shards from the upper shoulder exhibit tight, sharp curvature perfect for small flower buds, animal eyes, and high-specular star points. Artisans graded the shards into shallow wicker baskets, organizing them by curvature radius and optical clarity, ready for the delicate lapidary work of the stone cutter.

To transform irregular curved glass shards into the petals of royal lotuses, Mughal rosettes, and scrolling vines, the artisan employed the almas—a hand-forged iron stylus tipped with a natural uncut diamond crystal. The craftsman seated the curved glass shard face-up onto a heated bed of refined beeswax and pine resin (kil). This wax cushion conformed precisely to the convex underside of the shard, providing uniform pneumatic support that prevented the fragile glass from rocking or snapping under point pressure.

Holding the diamond scriber like a quill pen at a 45-degree angle, the artisan traced the intricate contours of paper cartoons directly onto the convex glass surface. The diamond facet scribed a continuous, razor-thin micro-fissure through the silica matrix. The artisan then gripped the shard with miniature soft-jaw iron pliers (chimdi) and applied a gentle downward snapping moment. The glass parted cleanly along the score line without chipping the delicate silver backing. Finally, the edges were dressed on a water-cooled, hand-turned sandstone lap, producing smooth, burr-free glass petals ready to be locked into palatial lime plaster.