Keilim4: 3
[ג] אֵיזוֹ הִיא גִסְטְרָא? כָּל שֶׁנִטְּלוּ אָזְנֶיהָ. הָיוּ בָהּ חִדּוּדִים יוֹצְאִין — כָּל הַמְקַבֵּל עִמָּהּ בַּזֵּיתִים מְטַמֵּא בְמַגָּע, וּכְנֶגְדּוֹ מְטַמֵּא בָאֲוִיר; וְכָל שֶׁאֵינוֹ מְקַבֵּל עִמָּהּ בַזֵּיתִים מְטַמֵּא בְמַגָּע, וְאֵין כְּנֶגְדּוֹ מְטַמֵּא בָאֲוִיר. הָיְתָה מֻטָּה עַל צִדָּהּ כְּמִין קַתֶּדְרָה — כָּל הַמְקַבֵּל עִמָּהּ בַּזֵּיתִים מְטַמֵּא בְמַגָּע, וּכְנֶגְדּוֹ מְטַמֵּא בָאֲוִיר; וְכָל שֶׁאֵינוֹ מְקַבֵּל עִמָּהּ בַּזֵּיתִים מְטַמֵּא בְמַגָּע, וְאֵין כְּנֶגְדּוֹ מְטַמֵּא בָאֲוִיר. שׁוּלֵי קוּרְפָיוֹת וְשׁוּלֵי קוֹסִים הַצִּידוֹנִיִּים, אַף עַל פִּי שֶׁאֵינָם יְכוֹלִים לֵישֵׁב שֶׁלֹּא מְסֻמָּכִין — טְמֵאִין, שֶׁלְּכָךְ נַעֲשׂוּ מִתְּחִלָּתָן.
Which [damaged utensil] is a gistera? Any [utensil] whose handles have been removed. [If] it had protrusions jutting out: Any [protrusion] that can contain olives transmits tumah via contact, and opposite [that area] transmits tumah via airspace; any [protrusion] that cannot contain olives transmits tumah via contact, but opposite [that area] does not transmit tumah via airspace. [If] it was resting on its side, like a katedra: Any [protrusion] that can contain olives transmits tumah via contact, and opposite [that area] transmits tumah via airspace; any [protrusion] that cannot contain olives transmits tumah via contact, but opposite [that area] does not transmit tumah via airspace. The bottoms of Kurfian [utensils] and the bottoms of Sidonian cups — even though they cannot stand without support — are tamei, since this is how they were initially made.
Keilim4: 4
[ד] כְּלִי חֶרֶשׂ שֶׁיֶּשׁ לוֹ שָׁלֹשׁ שְׂפָיוֹת, הַפְּנִימִית עוֹדֶפֶת — הַכֹּל טָהוֹר; הַחִיצוֹנָה עוֹדֶפֶת — הַכֹּל טָמֵא; הָאֶמְצָעִית עוֹדֶפֶת — מִמֶּנָּה וְלִפְנִים טָמֵא, מִמֶּנָּה וְלַחוּץ טָהוֹר. הָיוּ שָׁווֹת — רַבִּי יְהוּדָה אוֹמֵר: חוֹלְקִין הָאֶמְצָעִית. וַחֲכָמִים אוֹמְרִים: הַכֹּל טָהוֹר. כְּלֵי חֶרֶס מֵאֵימָתַי מְקַבְּלִין טֻמְאָה? מִשֶׁיִּצָּרְפוּ בַכִּבְשָׁן, וְהִיא גְמַר מְלַאכְתָּן.
An earthenware utensil that has three rims: [If] the inner one is higher, everything is tahor; [if] the outer one is higher, everything is tamei; [if] the middle one is higher, [then everything] from it and inward is tamei, [while everything] from it and outward is tahor. [If] they were even: R’ Yehudah says: We divide the middle [receptacle]. But the Sages say: Everything is tahor. From which point do earthenware utensils contract tumah? From when they are fired in the kiln, and this is the completion of their manufacture.