What is "Kadchod"?
Bava Basra 75a: Refer to 54:12:2:1.
Rashi: It is a gem.
Radak: Targum Yerushalmi of "Nofech Sapir" (Shemos 28:18) is Kadkedana v'Simulyana. It is a black pearl.
Malbim: Chazal say that it is Shoham 1 .
What is "Shimshosayich"?
Bava Basra 75a: In the future, Hashem will make a new source of light for us. One angel (or Amora) says that this is Shoham, and another says that it is Yashfeh (gems of the Choshen). Hashem decides that it will be "Kadchod", 'k'Dein uch'Dein' (both will be used).
Rashi citing Targum Yonasan: It is wood.
Rashi citing Menachem: This is [your servants,] like "Yeshameshune" (Daniel 7:10).
Rashi: They are windows, through which the Shemesh (sun) shines 1 . They make opposite it a barrier of colored glass, for beauty (Radak - the interior of the window is colored glass; when rays of sun shine on them, there is a beautiful appearance inside).
Rashi citing Midrash Tehilim: This is like "Shemesh u'Magen" (Tehilim 84:12), protrusions in the wall.
Radak: Perhaps the corners of the windows are Even Kadchod.
What are "[u'She'arayich] l'Avnei Ekdach"?
Sanhedrin 100a: Hashem will bring gems and pearls 30 Amos by 30 Amos, and carve out a hole 10 Amos by 20 Amos 1 , and erect them at the gates of Yerushalayim.
Targum Yonasan: L'Avnei Gomer. Rashi - this is the Targum of "Gachalei" (Vayikra 16:12, coals) is Gomerin. Yonason holds that Ekdach is an expression of "Kodechei Esh" (50:11). They are good stones that burn like torches (carbuncle). Radak - they shine like fire. This is like "b'Soch Avnei Esh His'halachta" (Yechezkel 28:14). The prefix Lamed in l'Avnei Ekdach is extra, like "Hargu l'Avner" (Shmuel II, 3:30), "veha'Shelishi l'Avshalom" (Divrei ha'Yamim I, 3:2).
Rashi: Ekdach are big rocks. The entire gap of the opening [of the gate] is carved out of them. The doorposts, lintel and threshold are all from the rock.
Radak: Perhaps the prefix Lamed in l'Avnei Ekdach and l'Avnei Chefetz teaches that the rocks that were initially in them, I will make them gems and pearls. The same applies to "v'Samtim l'Ya'ar" (Hoshe'a 2:14) and similar verses. Perhaps the simple meaning is true. Or, it is a metaphor for the great good that Yisrael will have, that if they want, they can make buildings of gems.
Malbim: Nofech is the stone [on the Choshen] for Yehudah; it is the sign of kingship. Sapir is the stone of Yisachar - Chachmah and Torah. These two found the building - the crowns of kingship and Torah. Shoham is Yosef's stone, a sign of success and wealth, the window of the sun - a sign that the sun will bring to them choice Peros. Ekdach was the stone of Levi, a sign of Avodah; this will be the gate - "Zeh ha'Sha'ar la'Shem Tzadikim Yavo'u Vo" (Tehilim 118:20).
100a: A Talmid mocked this, for nowadays, we don't find gems the size of a small egg. Shortly after this, he saw angels sawing holes in gems, with these exact dimensions.
Why does it say "l'Avnei Ekdach" with the prefix Lamed?
Radak: The Lamed is extra, like "Hargu l'Avner" (Shmuel II, 3:30), "veha'Shelishi l'Avshalom" (Divrei ha'Yamim I, 3:2).
What is "Kol Gevulech"?
Radak: It is not only Yerushalayim, rather, even bordering cities.
Malbim: The other parts of the building; they will have stones of the other Shevatim (refer to 54:12:3:5). This also teaches that all the Shevatim will be united; they will not be divided into two kingdoms any more.
What are "Avnei Chefetz"?
Rashi citing Targum Yonasan: They are useful rocks.
Radak: They are desired rocks.
Malbim: They are the stones [of the Choshen] of the other Shevatim (refer to 54:12:5:2).
