Abstract
Grey Ceramic culture in the second millennium B.C. have been the controversial issue in the Iranian Archaeology. Since most of the grey ceramics have been discovered from the burials, it remained some questions regarding the socio-economic conditions of the individuals. Also the rarity of settlement contexts have added some ambiguities as well. For this, material culture and archaeometrical analysis on the grey ceramics might be helpful to clarify some aspects of socio-economic condition such as, ceramic production, standardization and production organization. This paper will attempt to argue about some aspects of ceramic production in Qeytariyeh cemetery at Tehran plain with metric and chemical analysis. Ceramic analysis demonstrated a number of attributes which are including uniformity of decoration and dimensions, homogeneity of ceramic shapes, the variety of resources and preparation processes. The result of the analysis inspired us to draw the ceramic production organization through the standardization indicators. Finally, it can be proposed the scale and intensity of ceramic production in Qetariyeh might be the household industry or workshop industry.
Keywords: Metric Analysis, Chemical Analysis, Standardization, Production Organization, Qeytariyeh.

Introduction
Some sudden changes in cultural materials, the widespread cemeteries and unidentified settlement evidence in the second millennium B.C. encouraged scholars to study and propose some theories to interpret these cultural changes. According to the new researches and reassessment projects, it is needed to review and revise the chronology and older theories in this period.(Danti, 2013; Fazeli Nashali & Coningham, 2007; Hosseinzadeh et al., 2017; Fazeli, 2015; Sarlak, 2011; Farokhnia, 2020)
In fact, the comprehensive studies should be conducted to shed some lights on these ambiguities and restudy projects on some discovered collection would be necessary. Since just a few direct evidence related to the occupation have been found from the cemeteries, multidisciplinary studies such as archaeometrical analysis on the material culture (grey ceramics) might be helpful to study on the indirect evidence related to the ceramic production and production organization. In this paper, we have examined the standardization hypothesis in Qeytariyeh ceramic collection through the metric and chemical variabilities.
Qeytariyeh cemetery is located in the Shemiranat County, northern parts of Tehran and in the south of Qeytariyeh Park which is destroyed by construction of buildings and expanding residential areas in 1960s. The rescue excavation was conducted in 1968 and 1969 by Kambakhshfard (Kambakhsh Fard,1991). The restudy project was conducted in the National Museum of Iran (Farokhnia, 2020). The project provided us the opportunity to work on technological behaviors of the ceramic collection. 

Materials and Methods 
During the museum fieldwork, 1809 pottery vessels was registered. The ceramics were classified into different types or forms. The vessels present 23 types and 6 subtypes. The largest color category was grey (78.38). Of these 50% have burnished treatment techniques and 70% of the ceramic wares have fine texture bodies. 
The methodology combines the metric and chemical analysis to trace technological attributes. Metric indexes have been considered to evaluate the degree of standardization. Seven measurements were made on the pottery vessels: rim diameter, base diameter, wall thicknesses, height, pedestal height, spout height and neck height. 
The Potteries also were analyzed with a Portable Energy Dispersive X-Ray Florescence (ED- XRF), to study the compositional data and variability. Among these potteries, one hundred and eighty representative samples belongs to 21 type or forms were analyzed.

Disscusion
Metric indexes demonstrated the homogeneity of some dimensions in different types or forms. Besides that, some distinctive motifs have been used on the specific ceramic forms. 
Despite similarities in production techniques, the chemical composition of raw materials demonstrating two distinct type of clay sources. In this regard, availability of raw material, changing in technology, introducing new function, or even change in technical skills might be considered for changing in the raw source. The chemical composition of pottery samples shows that two distinctive geochemical groups does exist within our database. A calcareous clay composition with visible lime peddles whereas another clay is a siliceous deposit rich in Fe, Rb, and Nb. 
Among the collection, a large number of shapes associated with drinking function such as tankards, spouted jars, handled pitchers, spouted jugs which might be the most distinctive funeral function, have been identified. 
Obviously we don’t have access to the direct evidence of ceramic production in Qeytariyeh. However the recognized ceramic attributes would provide us the evidence of production organization.

Conclusion
Several Factors such as homogeneity in vessel form dimensions, manufacturing technology and chemical composition reflect specialized production in Qeytariyeh collection. In fact, most of the pottery vessels have very close dimensions in the specific form. The specialized production in Qeytarieh can be evidenced by standardized large number of final products, which show a constant formal and technological attribute. The high diversity in ceramic types and the ceramic surface treatment (burnishing surface treatment) brought to light the evidence of proxy of craft specialization and high skills of local producers. 
Thus our examination and documentation suggests Qeytariyeh ceramics have been produced by a given specialist workshop which are extremely homogeneous or standardized. 
Since both type of clay sources have been used simultaneously in manufacturing process, it can be deduced that probably two active Workshops were involved in production of entire manufacturing process.  
Taking in mind, that the calcareous clay has an advantage to form much easier and considering various range of skill level in production specific forms, it can be deduced that beside specialist also trainees were involved in manufacturing of end-product at least in some specific forms. This observation might explain the need for a shift in clay from siliceous to calcareous, as the raw source should also be in adjacent with professional skills. 
At the end, the result support the hypothesis household industry or workshop industry model for production organization in Qeytariyeh based upon standardized ceramic production and skilled producers in the ritual context.

Acknowledgements
Special thanks to Dr. Jebraeel Nokandeh Director of National Museum of Iran and his colleagues, Yousef Hassanzadeh, Nina Rezaee and Maryam Panahi. Also we want to thank Dr. Kamoldin Niknami for his comments on the text. We very much to thank Neda Tehrani and Nima Fakoorzadeh for photography of the collection.