{ "objects" : [ { "embark_ID" : 22573, "URL" : "https://webkiosk.gallerysystems.com/Objects-1/info/22573", "Disp_Access_No" : "PC.B.592", "_AccNumSort1" : "", "Disp_Create_DT" : "900 BCE - 300 BCE", "_Disp_Start_Dat" : "900 BCE", "_Disp_End_Date" : "300 BCE", "Disp_Title" : "Seated Figure", "Alt_Title" : "", "Obj_Title" : "", "Series_Title" : "", "Disp_Maker_1" : "", "Sort_Artist" : "", "Disp_Dimen" : "16.3 cm x 9.21 cm x 5.72 cm (6 7/16 in. x 3 5/8 in. x 2 1/4 in.)", "Disp_Height" : "16.3 cm", "Disp_Width" : "9.21 cm", "Dimen_Extent" : "", "Medium" : "jadeite", "Support" : "", "Disp_Medium" : "jadeite", "Info_Page_Comm" : "Attributed to Rio Pesquero, this figure appears to have been ritually burned in antiquity (a common trait of jades reportedly from this site). The iconography and modeled features of the piece reveal a complex but also very orderly statement pertaining to interrelated forms of verdant wealth -jade, quetzal plumes, and maize. ", "Dedication" : "Dumbarton Oaks Research Library and Collection, Pre-Columbian Collection, Washington, DC.", "Copyright_Type" : "", "Disp_Obj_Type" : "Structure", "Creation_Place2" : "Olmec", "Department" : "Pre-Columbian Collection", "Obj_Name" : "", "Period" : "Middle Preclassic", "Style" : "", "Edition" : "", "Curator" : "Bliss number B-592.70.OJ / DO number PC.B.592 Previously on record in Period/Style field: Middle Formative After the closing of the Lord of Creation traveling exhibith, an open architecture analysis of this objectc was perform by Tony (a.k.a. James H.) Frantz, Research Scientist of the Department of Scientific Research at the Metropolitan Museum of art to determine the nature of the stone. The analysis was made at our request due to the doubt about the composition of the stone mentioned in our records (diopside or jadite) and the fact that in the DO Olmect catalogue is a mention that the dark color in the stone was produce by ritual cremation of the stone. The analysis was posible due to the intervension of Julie Jones, Curator of the Africa, Oceania and the Anericas collection. The results (hard copy availabe in the dossier) are the following: Summary X-ray diffraction and x-ray fluorescence analysis confirm that the figure is carved from jadeitite and further indicate that the black vein material is pyrite. In the microsample on which the latter species was determined, no evidence was found for iron sulfates, oxides or other weathering products commonly occurring on pyrite exposed to the atmosphere and/or soil burial for extended periods. This anomaly, however, may likewise reflect anoxic conditions of burial such as may have been experienced on certain Olmec jades recovered from the Rio Pesquero region. Results Open-architecture x-ray diffraction analysis of the light gray rear surface of the figure yielded a well-defined pattern with more than thirty sharp lines between 5° and 80° 2q using Cu Ka radiation. This pattern was explicitly matched with a very low figure-of-merit to that of jadeite [Na(Al,Fe)Si2O6] using an unrestricted search of the ICDD PDF-2 database (see attached data sheet). Similar analysis of the dark gray underside of the figure yielded identical results (see attached data sheet). X-ray microdiffraction analysis of a very small composite sample of the black material occurring as sub-parallel veins in the rock fabric and exposed as an adherent crust in several places on the surface yielded a well-defined pattern with more than twenty sharp lines in the front and back-reflection regions using Cu Ka radiation. This pattern was successfully matched with a very low figure-of-merit to that of pyrite [FeS2] using an unrestricted search of the PDF-2 database (see attached datasheet). The sample pattern was fully accounted for by the reference pattern for pyrite with no significant residual lines. Specifically, no evidence was observed for anhydrous or hydrated iron oxides or sulfates. Open-architecture x-ray fluorescence spectrometry was performed on the same two areas. The spectrum obtained from the light gray rear surface is dominated by lines for iron and silicon, with weaker peaks for calcium, zirconium and titanium, while the spectrum obtained from the dark gray underside is similar except for weaker silicon lines and the presence of a very weak, low-energy sulfur line. Discussion The results indicate that the stone is a jadeitite--that is a rock comprised principally of the mineral, jadeite [Na(Al,Fe)Si2O6]. Pyrite [FeS2] is a well-recognized accessory mineral in jadeitite, although its occurrence in unaltered form as a surface expression exposed to weathering over extended periods is somewhat surprising. Olmec jades from the Rio Pesquero region reportedly have been recovered from river sediments rich in organic matter and, in such instances, may have sustained anoxic conditions sufficient to preserve surficial exposures of the sulfide species (George Harlow, personal communication). Indeed, the appearance of the Dumbarton Oaks figure resembles that of the gray jades with black veins that have been reported as deriving from this site (e.g., the jadeitite mask in the Dallas Museum of Art, 1973.17). The phenomenon of unaltered pyrite on the surfaces of such objects, however, calls for further study. At the very least, if the exposed veins document the original surface, their occurrence as such would seem to argue against the popular notion that the objects were subjected to deliberate heat treatment as part of cremations or other rituals. This and other questions could be explored through a more extensive mineralogical study of these objects. (by Tony Frantz, Metropolitan Museum of Art) Object was weighed in August 2009 with electronic scale (Swiss made: Mettler Toledo PB3002-S/FACT Topload Balance, from the B-S/FACT series), there was no previous weight on record (JAM) ", "Images": [ { "ImagePath" : "https://webkiosk.gallerysystems.com/Media/images/PC.B.592.S1.JPG", "ThumbnailPath" : "https://webkiosk.gallerysystems.com/Media/Thumbnails/PC.B.592.S1.JPG", "PreviewPath" : "https://webkiosk.gallerysystems.com/Media/Previews/PC.B.592.S1.JPG", "IIIF_URL": "http://iiif.gallerysystems.com/PC.B.592.S1.JPG", "IsPrimary" : "1", "_SurrogateID" : "22375", "Image_Type" : "", "Photo_Credit" : "", "Remarks" : "", "View" : "" } , ] }, ] }