parshat Terumah: tekhelet As Black As Kohl?

In a post last week, on the identification of tekhelet, I noted that Yefet ben Ali the Karaite states that tekhelet is black, and that Ibn Ezra rejects this in favor of Chazal who say that it is yarok (blue, in the "green" family). Then I turned to the Rambam and noted that he also identifies it as black, saying that it is wool dyed like the mixture in kochal {/kechol}, and later states that other blackening dyes are not valid. Kochal would seem to be black, from various sources in the gemara, and that, together with the mention of other dyes which make things black, suggest that he meant black and not dark blue, as some read Rambam. Further, that he says that the wool is dyed like the color mixture in kochal suggests that this is the color of the final product, not just the dye when it sits in a bottle.
Jastrow identifies kochal as stibnite, which was used even in Biblical times as a cosmetic for the eyes. From various sources we know that kochal is black.

Firstly, kohl is a modern cosmetic, an eyeliner, and the color of this seems to be black. This comes from the word kochal/kechol (and the equivalent in Arabic). (Though kohl then becomes a name for eyeliners in general, of any color.) Apparently, in Ancient Egypt:

First they tinged the eyelids green above, and below, then smeared a dark grey powder toward the eyebrows. The final procedure was to outline the eyes with black kohl, making them look larger and longer. Today, black kohl is still used by Bedouin women and the color "black kohl" is a popular eyeliner in any modern department store.

"Black kohl is also a color additive for food, not allowed in the US.

In terms of gemaras:
Chullin 88b speaks of mixing powdered coal (called שחור) and kohl. Chullin 47b} refers to a color which could be either black as kuchla {stibium} or else like ink {perhaps Indian ink}.

(Also, perhaps the expression "black as kohl." Read on.)

Thus, it truly seems that kochal is black, and it is to this black that the Rambam refers.

This brings us to an interesting question. The common expression "black as coal" -- did it originate as "black as coal" or as "black as kohl?" A search on the phrase "black as kohl" in google returns only 78 hits, many of which are simply some person who chose the name "black as kohl." Meanwhile, "black as coal" returns 127,000. Both make sense because both are black. Perhaps "black as kohl" came from a wordplay. Or, perhaps, "black as kohl" was the original, under lectio difficilior - people would chose the more familar "coal" in reinterpreting the expression.

Several of the uses of "black as kohl" occur in fiction. The second hit on google had it in contemporary Arab-American poetry.

It is summer and you are a boy
hunting birds and turning stones,
eyes as bright as the snow as it melts
from the Cedars beneath the summer sky.
Your hair is black as kohl,
your body olive brown,
your cheeks red as the rooftops of Hasroun,
red as the pomegranates your mother
in full burning youth
plucked from the cliffs of Hasroun.

Some examples based in India:
In The Death of Vishnu, used to describe hair color:

The buds would glow creamily in her tresses, black as kohl back then, and he would squeeze the petals between his fingers to release their fragrance and perfume her hair.

In this posting, used to describe night:

After some haggling and a maharajahs ransom, a rickshaw began peddling me to Bhubaneshwar, some 40 miles through a howling, screeching, black as kohl Indian night.

An example of it used to describe the sky in Colorado:

when the sky to the east is black as kohl

On the other hand, coal is certainly used to describe the color black as well. Consider the expression "jet black hair," or "jet hair." Jet is "A dense black coal that takes a high polish and is used for jewelry" and, as an adjective, is defined by the dictionary as "Black as coal."