New Seal with King Hezekiah's name

The remains of a 10th  cent. BC foundation wall
that is part of the Large Stone Structure that Israeli
archaeologist Eilat Mazar claims is part of David’s palace.
Ophel excavations where the Hezekiah seal was discovered.

In 2005, on the eastern slope, east of the Temple Mount in Jerusalem, Eilat Mazar uncovered the remains of a fine monumental palatial structure  known as a Large Stone Structure, supported by a Stepped Stone Structure (built between the LB2 and IA1.  Possibly the Millo of 1 Kgs 9:15–24; 2 Chron 32:4–5),  dating to the time of David and Solomon (9th to 8th cent. BC). Jane M. Cahill, “Jerusalem at the Time of the United Monarchy. The Archaeological Evidence,” in Jerusalem in Bible and Archaeology: The First Temple Period, ed. Andrew G. Vaughn and Ann E. Killebrew, SBL Symposium Series 18 (Atlanta, Ga.: SBL, 2003), 32–54, especially 52. Mazar believes this to be the remains of the palace of David, which dates to the early 10th cent. BC,  although she has taken strong criticism for her claim.  Based on the pottery in a sealed locus, uncovered by all three excavations (Kenyon, Shiloh, and E. Mazar), Amihai Mazar confirms that the Stepped Stone Structure and the Large Stone Structure are joined together and were constructed in the Iron Age I. Mazar, Amihai. “Archaeology and the Biblical Narrative: The Case of the United Monarchy.” In One God - One Cult - One Nation: Archaeological and Biblical Perspectives, edited by Reinhard Gregor Kratz and Hermann Spieckermann, 29–58. BZAW 405. Berlin: De Gruyter, 2011 41.

The discovery of several bullae inscriptions also supports the use of the building by royalty. Among the names on some 51 seals (bullae) recovered so far, are the names of two ministers of King Zedekiah’s court, the last king of Judah. “Yehuchal Ben Shelamayahu, son of Shovi” and “Gedaliah Ben Pashchur” are two of the four officials who plotted to kill the prophet Jeremiah (Jer 37:3; 38:1). Another name on the bullae, “Gemaryahu ben Shafan,” is mentioned as being King Jehoiakim’s scribe towards the end of the First Temple period (Jer 36:10). Lawrence J. Mykytiuk, Identifying Biblical Persons in Northwest Semitic Inscriptions of 1200-539 B.C.E. (Society of Biblical Literature, 2004), 139–147; Mazar, Eilat. The Palace of King David Excavations at the Summit of the City of David: Preliminary Report of Seasons 2005-2007. Jerusalem, Israel: Shoham Academic Research and Publication, 2009, 54–56; Mazar, Eilat. “Did I Find King David’s Palace?” Biblical Archaeology Review 32, no. 1 (2006): 16–27, 70.

Now another bullae seal inscription, with the name of King Hezekiah (II Kings, Isaiah, II Chronicles 727–698 BC) has been announced (Dec 2, 2015),  during the wet sifting of the soil from Ophel excavations under the direction of Eilat Mazar. Temple Mount Sifting Project. It was originally excavated in 2009 during Ophel Excavations, but just recently published. It reads “Belonging to Hezekiah [son of] Ahaz king of Judah”
Dr. Eilat Mazar said:

“Although seal impressions bearing King Hezekiah's name have already been known from the antiquities market since the middle of the 1990s, some with a winged scarab (dung beetle) symbol and others with a winged sun, this is the first time that a seal impression of an Israelite or Judean king has ever come to light in a scientific archaeological excavation.” 

See the announcements at the Hebrew University of Jerusalem  and the Israel Ministry of Foreign Affairs. The Bible describes King Hezekiah as "He trusted in the Lord, the God of Israel, so that there was none like him among all the kings of Judah after him, nor among those who were before him." (2 Kings 18:5).

Dr. Eilat Mazar explains her find in this video LINK

 More on King Hezekiah's unprovenanced seals (over 21) and other seals of Hezekiah's high officials, indicating that Judah was an active kingdom can be found in Robert Deutsch's Presentation.

Dr. Leen Reitmyer adds some further insights about the location of the find at his site.