Mishnah Niddah 2:7: What is [considered] red? Like the blood of a wound. Black? Like ink-sediment; [black which is] deeper than this is impure, paler than this is pure. And [what is considered] like the brightness of a crocus? Like the clearest [shaded petal] in it. And like earthy waters? [Like the reddish earth] from the Bet Kerem valley, with waters floating over it. And [what is considered] like diluted wine? Two parts water, and one [part] wine, from wine of Sharon.

אֵיזֶהוּ אָדֹם, כְּדַם הַמַּכָּה. שָׁחֹר, כַּחֶרֶת. עָמֹק מִכָּן, טָמֵא. דֵּהֶה מִכָּן, טָהוֹר. וּכְקֶרֶן כַּרְכּוֹם, כַּבָּרוּר שֶׁבּוֹ. וּכְמֵימֵי אֲדָמָה, מִבִּקְעַת בֵּית כֶּרֶם, וּמֵצִיף מָיִם. וּכְמָזוּג, שְׁנֵי חֲלָקִים מַיִם וְאֶחָד יַיִן, מִן הַיַּיִן הַשָּׁרוֹנִי:

Mishnah Niddah 3:1: Regarding a woman who miscarries a piece [of flesh], if there was blood with it, she is impure; it not, she is pure. Rabbi Yehudah says: either way she is impure.

הַמַּפֶּלֶת חֲתִיכָה, אִם יֵשׁ עִמָּהּ דָּם, טְמֵאָה. וְאִם לָאו, טְהוֹרָה. רַבִּי יְהוּדָה אוֹמֵר, בֵּין כָּךְ וּבֵין כָּךְ, טְמֵאָה: