Inlay history: about inventor and innovator of signet, there are various narratives among seal makers and artists. But what is noteworthy is that, it is not well understood, who has created the first seal, Persian encyclopedia says: nobody knows the start of this art, and whatever has been mentioned regarding this issue is associated with legend. Some of inlay masters still believe, signet art is the miracle of Abraham the prophet.
Egyptian artisans have adopted this method, just like other arts and crafts from Copts. Several pieces and plates, which on them have been mosaicked with wood and bone, was found near in EINOLSAIREH, near to Cairo in early period of Islam and most of them are available in Islamic industry museum of Cairo or Berlin museum. And one of its finest samples of this industry is at metropolitan museum.

Other historical works and samples of this art are:

1-inlaid rostrum in ATIGH mosque of SHIRAZ city, dating back more than a thousand year of antiquity.
2-main porch roof of ATIGH central mosque of SHIRAZ city, related to eight century AH (fourteenth century AD).
3-inlayed doors of dreamed palace which was belonged to TEYMUR GORKANI and was called as cheery in SAMARGHAND city and doors of his tomb in 807 AH (1405 AD).
4-walnut doors and bone veneer and other woods which were made by an artist called as HABIBOLLAH in the year 999 AH (1591 AD) which is kept in berlin museum.
5-the doors decorated with geometric shapes of flower and bush, from BOKHARA city, which is available in museums of Victoria and Albert in London city.
6-wooden rostrum of LENBAN mosque in Isfahan city with geometrical designs and silver components, related to 1114 AH (1702 AD). Top of flourishing and evolution in this art was in SAFAVID era. During this time, many artists from all corners of Iran were going to Isfahan, which was capital city of Iran in that time. And forgotten arts of this country were re-established and artists, while working in inlaying, tiling and Chinese knots, were encouraged to repair the old shrines, holy places and constructing the buildings. Later in QAJAR era, the authorities did not care for art and artists. So, all arts lost their credits and masters and professors of this art were living in worst condition.
In 1307 SH, in early era of PAHLAVI, industry school was established by efforts of MOHAMMAD GHAFARI (KAMALOLMOLK). And this school gave prosperity and development to the said art. After that, many inlay work shops were made in ex-ministry of culture and art.
The remained works of some artists in Isfahan, Tehran and Shiraz are consisted of an inlayed room of 7 in 7 meters with all existed tools in Marble palace which took 4 years to build it.
Inlayed hall of national consulate assembly with 400 square meters of inlaying.
Inlay art after the Islamic revolution in signet work shop of ex-ministry of culture and art, got a new name and handed over to ministry of culture and higher education. And since then, direction of plans has been changed and with removing the foreign designs, more attention was given to traditionalism and also seal inscriptions entered the signet.
Definition of inlay: signet is combination of regular polygons with some different sides and was formed from various materials in different colors.
Signet is of exact and heavy works handicrafts. And its production needs accuracy and patient. Polygons come in five, six, seven, eight or ten dimensions.
In DEHKHODA dictionary, inlayer was explained as: the person, who makes designs with pieces of bones on the wood. Inlaying is the act of inlayer.

Persian encyclopedia, about inlaying and seal making says:

It is an art of designing the level of objects, just like mosaic with small triangles.
Different designs of signet always is in the form of regular geometric figures. They are designing the geometrical shapes by keeping the small triangles, beside each other. They are making the triangles from wood, metal and bone. As much as triangles are smaller and delicate, the signet is finer. In designing a signet, to make the smallest unit of geometric, minimum three triangles and to make the biggest, maximum 400 triangles are necessary.

The oldest and remained inlaid art works are:

1-shrine box of Imam MUSA BIN JAFAR (AS) and Imam JAVAD (AS) in KAZEMEIN city, which is related to King Ismail SAFAVID, and was built by Master MOHAMMAD JOMAA in the year 906 AH.
2-shrine box of Imam HASAN ASGARI (AS) in SAMERE city shrine box of Imam ALI ALNAGHI, which is related to same era and same master.
3-Inlay shrine box of NARGIS KHATUN (AS) (mother of Imam MAHDI (AS), the twelfth Imam of Shia people), which was built and installed in the said era.
4-beautifu and valuable work of entrance door in four garden schools in Isfahan city, which was repaired by masters of this art, many times.
5-inlay shrine door of Imam`s son, the SHAH REZA (AS), in QOMSHE city (SHAHREZA), in king TAHMASB SAFAVID era.
6-inlay shrine box of ALI (AS) was made at the time of KARIM KHAN ZAND and installed at the time of LOTFALIKHAN ZAND.
7-inlay shrine box of SEYEDAL SHOHADA (AS) and ABOLFAZL (AS) in KARBALA city.
8-inlay shrine box of ZEINAB (AS) in Syria.

Raw materials in producing the signet:

All kinds of wood (ebony-betel nut-walnut-log wood-jujube-orange-KAHKAM-aspen)
All kinds of bone (bone and ivory of elephant-bone of camel-bone of horse)
Metal wires (brass-aluminum and sometimes silver)
Pearl-thread of fin-gelatin-lacquer-
Work tools and instruments in art of inlaying:
General tools such, as hammer, saw, drill, Auger and…….
Main and special tools, such as all kinds of saw, all kinds of rasp, all kinds of shaver, vise, locked ruler, FINAGE, all kinds of pitcher, special glues and……..

Production processes of signet:

First, many kinds of woods and bones, should be collected, and then cut it with special tool, for the length of 30 cm and diameter of 1 to 5.2 mm and make some triangles. After rasping, all sides will be according to the design. To complete it, metal wires in triangle shape are necessary, and for this case also, some procedures are necessary. Then to make the inlay, the master must draw some designs for the project. After that, the triangles which were made out of wood, bone and metal are going to be kept beside each other wisely by the artist with gelatin and will be tied by tread, and they will call this case as vane. After some hours, they open the treads and keep them beside each other and glue them. Masters call this section as TUGLU, next phase is flower complex. By a round metal wire which has been made as a regular hexagon, and master are calling it as SHAMSE, they glue them in around of six wires by gelatin and tie them by glue. And the result is a star design. These projects will be repeated until become the desired design. And then will be kept under pressure and press and with multiple cutting stages and pasting some very thin layers of wood around them, the initial design of a signet is produced. All these procedures, from the beginning up to here, are contained of 400 work stages.
Inlays, on the basis of design, color, shape and dimensions of the used place on work surface are pasted by special gum and will be designed by creating the different designs and making proportion of all designs by inlay. And after some repairs, rasping, sanding and primer and finally, grinding and smoothing the surface of the inlay, the work is ready for lubrication and polishing by special materials such as other sealer, Keeler and polyester. Desirability of a good inlay, depends on small design and regularity of design. All these are depending on skill of master in preparing the raw materials and the way of using it, patient and much accuracy.