J. Kala-ilan (indigo) as Imitation of Tekhelet–A Clue to the Determination of the Colour of Tekhelet

It is somewhat strange that none of the authors who, so far as I know, treat seriously of the determination of the Tekhelet colour1 has taken advantage of the fact recorded in the Talmud that Tekhelet was visually indistinguishable from kala-ilan which is indigo2 according to the Aruch, the authoritative lexicon of the Talmudim and Midrashim.3

The Aruch also renders אסטיס (Isatis tinctoria wood) by indigo. “Isatis is indigo Arabic Nil.”4 The Arabic authors designate both indigo (Indigofera tinctoria and argentea) and Isatis tinctoria by the same word nil (or nileh).

As isatis is designated by its Greek or Latin name, Kala-ilan doubtless denotes the genuine indigo.5 It would be of some interest to trace the derivation of this composite expression.

The Talmudic name for indigo is in all probability a loanword from India. The Indian names for indigo are nilini, nilam, nili. The Sanscrit kala properly means black but the deep indigo blue is also called by that name.6 May not קלא אילן kala-ilan mean kala derived from trees (ilan – tree) in contradistinction to the deep blue of mineral origin (the “ancient blue,” “Egyptian,” or “Alexandrian blue”).7 In view of the fact that the indigofera plant often attains the height of 5 feet it might well be popularly called ilan (tree).8 Or may perhaps kala-ilan be a corruption of kala-nilan, the black or dark nilan (indigo) or of kala-lan (lan = indigo in Chinese)?

Deep indigo blue may thus be taken as reproducing the colour of Tekhelet.

In deep shades as Professor Green of Leeds has informed me indigo is not a pure blue.9

Most people would indeed be unable to distinguish deep indigo, from deep pure blue, but to the experienced eye a slight reflex of violet is visible. Compare Pliny 


From this the most indigo influence comes from India … when it is rubbed black but in washing it makes a wonderful mixture of purple and blue.  Ab hoc maxime auctoritas indico Ex India venit … cum teritur nigrum at in deluendo mixturam Purpurae caeruleique mirabilem reddit.10


Maimonides remarkably enough makes no mention of kala-ilan in connection with Tekhelet imitations. He names two such colours isatis and שחור (shahor), black. The latter word has been misunderstood: shahor here is not used in the ordinary sense of black but is the Hebrew rendering of the Sanscrit nil by which the Arabs in Maimonides’ times as at the present day designated indigo.11 Shahor in Maimonides is thus the equivalent of kala-ilan (indigo) in the Talmud.

  1. Sachs identified kala-ilan as an adaptation from kallainon-callainum. In connection with his suggestion that גלקטיגון the rendering of the Yerushalmi for תחש is a corruption of galairon kallainon, that author observes:


“At any rate, this gloss is already recognized by Musaffia, but is misunderstood by his successors; designated as Indigohlan.

“For” kelailon “one spoke search” kelainon “and through the accidental separation of the word into two one thought, overlaid by (ilan) Ilan of a tree or a bush was driven, caused this indigo-colored wave to be sold for that. “

“Jedenfalls ist durch diese Glosse das von Musaffia bereits erkannte, aber von seinen Nachfolgern unverstandene קלא אילן (kala-ilan) erklärt (Nedar.12 41 u. sonst) das werder einen Stoff noch eine Pflanze bezeichnet, sondern die blaue Farlu, vom Aruch als Indigohlan bestimmt.

“Für “kelailon” sprach man such “kelainon” und durch die zufällige Trennung des Wortes in zwei dachte man, durch (ilan) אילן verlastet, an einen Baum, oder eine Staude. Bertrug, der mit dem (Tekhelet) תכלת dem verschriftsmässig gebotenen getrieben wurde, veranlasste, diese indigoblau gefärbte welle für jenes zu verkaufen.”13


Jastrow (Dictionary of the Talmudim, etc. s.v. קלא אילן) adopting the derivation proposed by Sachs, states plainly that kala-ilan is an adaptation from the Latin callainum.

The determination of the etymology and precise meaning of kallainon presents serious difficulties.

Pliny mentions a certain gem under the name of callais or callaina. In one place Pliny says that the callais resembles the sapphire but is of a paler nuance “callais sapphirum imitatur, candidior et littoroso mari similior.” In another the Roman naturalist describes its colour as “e viride pallens,” pale green. It would appear that callais and callaina are to be distinguished.

The kalais has been identified with the turquoise. The turquoise, however, is generally blue, though certain varieties present a green playing into bluish. The standard thesauri asserts on the authority of an anonymous writer that the Greek kallainon chroma answers to the Latin color venetus.

Salmasius14 tries to show that the gem derived its name from the colour, not vice versà.

“To kallainon chroma” (“τὸ καλλάϊνον χρῶμα”) (“the beautiful color [the color that shifts between green and blue]”) would seem to be a greenish blue colour.

Several references to vestes callaina “kallaina imatia” (“καλλάϊνα ἱμάτια”) (“beautiful garments [garments whose color shifts between green and blue]”) occur in classical literature and also in certain inscriptions.

If as Sachs holds kala-ilan is identical with “kallainon” (callainum) it would follow that Tekhelet was a greenish blue. This is, however, not very probable. All the evidence at our disposal points to the identification of kala-ilan with indigo which is not a greenish blue.

“Kalainos” (callainus-a-um) occurs only as a colour designation, never as the name of a dyestuff: kala-ilan in the Talmud denotes the colour and the dyestuff producing it. “Kallainon” nowhere expressly appears as synonymous with indigo (indikos, indicum).

On the other hand, indigo (הינדיקון) never occurs in the Talmudim and the Midrashim. Should “kallainon” be identical with “indikos” (indigo) we should have to account for the phenomenon that while the Greeks and the Romans termed indigo variously by “kallainos” and “indikos,” the Jews exclusively adhered to the former appellation. Though, from the fact that only the latter has survived in the European languages, it would appear that the former if used for describing indigo must have been at all events the less common one.

Bochard, though he makes no mention of kala-ilan, refers to “kallainon” asserting that “kallainos” and “iakinthos” denote one and the same colour, his authority being Epiphanius: “

From purple, indeed, and from deep red and hyacinth, to show the beauty of the wool.

Ia de purina, ina eite kokkera endulata kai jakinthina ina deikse ten kallainen erean.15

Bochart makes no attempt to define the colour designated by “kallainos.” It is, I think, within the realm of probability that “kallainen” here is a textual corruption of “kalanilen” or “kalailan” kala-ilan (קלא אילן) = indigo.16

The sense of the passage in question does not, however, require identity of colour with “iakinthos” but only a certain degree of similarity. Epiphanius writes here in an homiletic vein, his object being to interpret the symbolic signification of the coloured fillets adorning the angels depicted in the Apocalypse of John. These, as he explains, are emblematic of the national colours of the Assyrians, Babylonians, Medes and Persians respectively. It may be that the favourite colour of the national dress of the Persians in Epiphanius’ time was a greenish blue such as was described by the term “kallainos.”

It is perhaps the “chroma kallainon” which is meant in the Mishnah Berakhot 1a where the time for the reading of Shema in the early dawn is said to begin according to R. Eliezer משיכיר בין תכלת לכרתי from the moment when כרתי becomes distinguishable from Tekhelet. Karti is used in the Talmud for designating leek and a certain colour variety. As a colour designation the word does not necessarily mean leek-green exactly reproducing the pale green of the leek-plant. It is rather a generic name for green. Similarly “prasinos” in Greek from “prason” (leek) denotes green.17 As the name of a coloured fabric18 כרתי may mean a greenish blue.19

As the fabric appears to have been highly expensive it should perhaps be identified with that variety of purple, the colour of which Pliny describes as “austerus in glauco et irascenti similis man.”

Dr. Dedekind is in possession of a specimen of greenish blue purple dyed by Lacaze-Duthiers.20



  1. Bochart, Braun, Adolf Schmidt, G.E. Leiner, Israel Lifschutz (Cf. Excursus to Ch. VII), and Dr. Dedekind.
  2. Or, indicum. On Isatis tinctona, as a substitute for indigo, see: Jaubert, La garance et l’indigo. Paris (1900), p. 63, with special reference to England in the 16th cent.
  3. That the Tekhelet colour was regarded by the Tanaites as well as by Philo and Josephus as akin to black is evident from Sifre Num.
    ד אלעזר ב״ר שמעון אומר למה נקרא שמה תכלת על שם שנתכלו המצרים בבכורות שאמר ויהי בחצי הלילה וה״ הכה כל בכור
    Cf. Rashi ib. ע״ש שיכול בכורות ומכתם היתה בלילה וכר
  4. Aruch, S.v.
  5. See: Tosephta,״בור קלא אילן שרשם בעצי אשירה״ עבודה זרה, פרק ג׳ Read:שרשו, and compare: I. Depievre’s account of the manufacture of indigo: “On fait tomber les feuilles dans de très grandes cuves en maçonnerie dîtes trempoires. On voit dans de l’une de ces batteries un paniken ou contre-maître à turban rouge et huit coolies ou ouvriers qui battent l’infusion avec des batons pendant environ deux heures, etc.” Depievre, Traité de la teinture, v.III. Paris ( 1893), “Indigo.” The indication about the fastness of Kata Ilan also supports the identification with indigo. See: Depievre, ib.
  6. Alkali is the name of a certain Indian sect whose members dress, as a matter of religion, in no other colour but dark blue. See: British Encyclopedia, 11th ed., “India.”
  7. See: Fremy, Encyclopédie Chimique. Paris, 188.
  8. See: ירושלמי כמא׳ פרק ה׳ הלכה ל׳. סוכה ל״ה; ע״א רשי׳ ר״ה חייבין בערלה, v.10, p. 95.
  9. Editor’s note: Rabbi Herzog has attached a sample of colour on p. 204 of the original work, which appears as a gray spot only in our copy. The same page contains the following text beneath the sample: “Sample of deep indigo. Kindly supplied to me by Monsieur Vallette, Chimiste en-Chef at the Fabrique des Gobelins, 42 Avenue des Gobelins, Paris. M. Vallette’s reply with reference to the scientific definition of the nuance of the sample:
    ‘Ministère de l’Instruction Publique et des Beaux Arts, manufacture nationale des Gobelins. Paris, le 26 Mar. 1914.
    Cher Monsieur, Excuser moi si j’ai tant tardé à vous envoyer l’echautillon d’indigo… D’après la classification des couleurs de Chevreul, l’indigo est d’une coleur bleu-violet. Veuillet … Ch. Vallette.'”


    ‘Ministry of Public Instruction and Fine Arts, National Manufacture of Tapestries. Paris, 26 Mar. 1914
    Dear Sir, Excuse me if I were so late sending you the indigo … From the Chevreul color classification, the indigo is a blue-violet color. Veuillet … Ch. Vallette. ‘”

  10. Pliny, Hist. Nat., book 35, para. 27.
  11.  Nil in Hindustani denotes black as well as dark blue. “The origin of the Greek and Roman name, Nilus is quite unknown” (Encycl. Brit. 11th ed., s.v. “Nile”). Perhaps it is connected with the Indian nil, black, dark, the dark, or black river. Cf. I Chr. ch. 13, v.15: His, ch. 13, v.3. Cf. Arabic: Nil-Misr. the Nile of Misr (Egypt).
  12. Mistake for Menahot 41. Sachs has misunderstood Musaphia. The latter’s note א״ב ב״י בלשון יוני מין צבע דומה לתכלת refers to the Aruch’s statement פירוט אינדיקן, not to קלא אילן. See: Aruch, s.v.קלא אילן
  13.  Sachs, ibid., v.I, p. 132. All this is bad philology. Kelainos (Greek for dark amber perhaps connected with the Indian “kala”) has really nothing to do with “kallainon.” I have not found “kelailon” in any of the thesauri I have consulted.
  14.  Saumaise, Claude de, Caji Julii Solini Polyhistoria, Trajecti ad Rhenum (1689), p. 167.
  15. Epiphanius, Alogie, ed. by Higby, sect. 34, haeres, p. 954.
  16.  Epiphanius being a native of Palestine would designate indigo by the name current in that country. Epiphanius, it may be mentioned, is also said to have been of Jewish extraction.
  17. Deep as well as pale shades.
  18. כרתי also occurs as the name of a certain gem. See Targum 1,6 כרתינון aand LXX “prasinon” for שחם. Perhaps כרתי as a gem “kalais.”
  19. See:גיסין ל״א ע״ב גוהרקא דד בא ופרוס עליה סרב לא דברתי Cf.רבנו יונה אלפסי ברכות פ״א משנה ב׳ where the Aruch is wrongly quoted as saying:״כרתי הוא צבע הינדרי״ש״. The writer’s mistake was occasioned by a false construct of: “תוספות חוליו מ״ק ע״ב ד״ה “ירוק כרתי ib., in the Vilna ed. of the Talmud. Cf. also:
    פרשה מקוהלת ברכות פרק ס׳”תכלת היא צבע ירוק רומא קצת לכרישיך
  20. Dedekind, “La Pourpre verte,” Archives de Zoologie, exp. et gen. (1898).