Ptil Tekhelet, The ancient Bibical blue (Murex trunculus) with a cotton tsitsit

Description

Rambam's
Tethering
Murex trunculus
Ancient Tekheket
Adult size
In his doctoral thesis (London, 1913) on the subject, Rabbi Herzog named
Murex trunculus
as the most likely candidate for the dye's source. Though
M. trunculus
fulfilled many of the Talmudic criteria, Rabbi Herzog's inability to consistently obtain blue dye (sometimes the dye was purple) from the snail precluded him from declaring it to be the dye source.
According to Zvi Koren, a professor of chemistry,
tekhelet
was close in color to midnight blue.
[18]
This conclusion was reached based on the chemical analysis of a 2000-year-old patch of dyed fabric recovered from
Masada
in the 1960s.
[19]
The sample, shown to have been dyed with
Murex snail
extraction, is a midnight blue with a purplish hue. Additionally, in 2013, Na'ama Sukenik of the
Israel Antiquities Authority
verified a 1st-century CE-dated fragment of blue-dyed fabric to have used
M. trunculus
as the source of its pure blue color.
[20]
In the 1980s, Otto Elsner,
[21]
a chemist from the Shenkar College of Fibers in Israel, discovered that if a solution of the dye was exposed to
ultraviolet rays
, such as from sunlight, blue instead of purple was consistently produced.
[22]
In 1988, Rabbi Eliyahu Tavger dyed
tekhelet
from
M. trunculus
for the
mitzvah
(commandment) of
tzitzit
for the first time in recent history.
[23]
Based on this work, four years later, the
Ptil Tekhelet
Organization was founded to educate about the dye production process and to make the dye available for all who desire to use it. The television show
The Naked Archaeologist
interviews an Israeli scientist who also makes the claim that this mollusk is the correct animal. A demonstration of the production of the blue dye using sunlight to produce the blue color is shown. The dye is extracted from the hypobranchial gland of
Hexaplex (Murex) trunculus
snails.
[14]
פתיל תכלת של עמותת פתיל תכלת מופק מחלזון ארגמן כהה קוצים.
פתיל תכלת זה מקובל על ידי תלמידי חכמים רבים ובראשם הרב הרצוג זצ"ל, רבה הראשי של ארץ ישראל כפתיל התכלת המקורי שעל ידו נעשית המצווה.
פתיל התכלת נקשר על ידי תלמידי ישיבה בישראל.