Keilim6: 3
[ג] שָׁלשׁ אֲבָנִים שֶׁעֲשָׂאָן שְׁתֵּי כִירַיִם, נִטְמֵאת אַחַת מִן הַחִיצוֹנָה, הָאֶמְצָעִית הַמְשַׁמֶּשֶׁת אֶת הַטְּמֵאָה — טְמֵאָה; הַמְשַׁמֶּשֶׁת הַטְּהוֹרָה — טְהוֹרָה. נִטְּלָה הַטְּהוֹרָה — הֻחְלְטָה הָאֶמְצָעִית לַטְּמֵאָה. נִטְּלָה הַטְּמֵאָה — הֻחְלְטָה הָאֶמְצָעִית לַטְּהוֹרָה. נִטְמְאוּ שְׁתַּיִם הַחִיצוֹנוֹת, אִם הָיְתָה הָאֶמְצָעִית גְּדוֹלָה — נוֹתֵן לָזוֹ כְּדֵי שְׁפִיתָה מִכָּאן וְלָזוֹ כְּדֵי שְׁפִיתָה מִכָּאן, וְהַשְּׁאָר טָהוֹר. וְאִם הָיְתָה קְטַנָּה — הַכֹּל טָמֵא. נִטְּלָה הָאֶמְצָעִית, אִם יָכוֹל לִשְׁפּוֹת עָלֶיהָ יוֹרָה גְדוֹלָה — טְמֵאָה. הֶחֱזִירָהּ — טְהוֹרָה. מֵרְחָהּ בְּטִיט — מְקַבֶּלֶת טֻמְאָה מִשֶּׁיַּסִּיקֶנָּה כְּדֵי לְבַשֵּׁל עָלֶיהָ אֶת הַבֵּיצָה.
Three stones were made into two stoves: [If] one of the outer [stones] became tamei, [the part of] the middle [stone] that serves the tamei [stone] is tamei, [and the part] that serves the tahor [stone] is tahor. [If] the tahor [stone] was removed, the middle [stone] becomes entirely tamei. [If] the tamei [stone] was removed, the middle [stone] becomes entirely tahor. [If] the two outer [stones] became tamei: If the middle [stone] was large, one allots as much as is needed to set [a pot] on either side and the remainder is tahor; but if it was small, it is entirely tamei. [If] the middle [stone] was removed: If a large cauldron can be set upon [the stove], it is tamei. If [the stone] was returned, it is tahor. If [the stone] was plastered with clay, it will be susceptible to tumah from when one heats it enough to cook the egg on it.