תכלת

בין תכלת ללבן

Teckelet is a color similar to the color of the sea and was used to dye a string on the tzitzet. Over the exact way of making תכלת has been forgotten. In the last hundred years a number of people have tried to identify the way in which to make תכלת. Until today, the matter remains disputed. Below is a video of one opinion as to how to make תכלת.

בין תכלת לכרתי

The Mishnah also mentions the opinion of רבי אליעזר who says the earliest time to say the shema is when one can tell the difference between תכלת and כרתי. Many identify כרתי as a vegetable called "leek". Below is a picture.