The center stone button seal is from Period IV (2900-2400 BCE), while the right most stone button seal is similar to ones from Period II (3500-3400 BCE) and Period III (3400-2900 BCE).
"Stone seals appear in Mundigak in their most crude form of
Button seal from the upper layers of Mound AB. Although this seal was found in mixed deposits dating to the Harappan and Late Harappan Periods, the carving suggests that it is actually an Early Harappan seal, dating to around 2800-2600 BCE.
In Kot Diji phase sediment that had washed into the street, Brad Chase discovered a button seal (close-up in 44) quite similar to seals recovered from the site of Rehman Dheri in to the Northwest in the Gomal Valley.
On this Kot Diji phase steatite button seal from Harappa (H2000-4495 / 9597-01), traces of blue-green glaze can be seen (upper center and left center). Similar seals have been found at other Kot Diji period sites and even in distant Central Asia.