Fourteen silver ingots were found among the Cirebon cargo. Some of these were lying individually around the periphery of the tumulus, while others were found in groups of two or four nearer the wreck itself; all were spread out among the cargo of Chinese ceramics from the kilns in the south-east of the country. Eleven rectangular ingots with wider rounded ends measuring up to +/- 18 cm x 8 cm x 2. 5 cm (Type I) were found at a height of 50 cm above the sea bed.
Three ingots of a different shape, rectangular with folded in corners and measuring up to 16 x 12 cm (Type II), were found higher up inside the wreck, at a height of 1m, right in the heart of the tumulus.
Ingots similar to the Type II Cirebon ingots were also found in much greater numbers among the Intan cargo (80 were recovered during the excavation – 14 more are known to lie elsewhere). These varied in length between 10.3 cm and 14.5 cm. Their peculiar shape with folded in edges is due to the way they were made, according to Mr Flecker: as they were cast in individual univalve moulds, any excess metal was folded back onto the body of the ingot like a leaf once it had cooled.
These fourteen ingots are not all exactly the same size, and consequently do not weigh the same either (varying between 428 g for the smallest and 2,419 g for the largest). The silver ingots in the Intan wreck are inscribed with their guaranteed weight in Chinese characters, but this does not seem to be the case with the ingots from the Cirebon: so this was probably a simple way of packaging the raw material. Might some of these ingots originate from China nonetheless? It is known that from the end of the 8th century and in particular in the 9th century, the silver production centred on the mines in Fujian, Zhejiang, south Jiangxi and Hunan was really booming. It was common for private banks and currency exchange institutions to issue silver ingots. These ingots were inscribed with their guaranteed weight in liang, a stamp for which they were valued by merchants for a long time from the 10th century onwards, and used in business transactions carried out not only within the country but also in continental and insular South-East Asia.
Two samples of Type I ingots analysed at the University of Liège Archaeometry Laboratory (PIXE) are made of silver of between 870 and 900 thousandths, alloyed with gold (> 2%), copper in very variable proportions and lead in the proportion of 0.4 % and 1.3 %.