Red jasper tit amulet of Nefer/Aset's Knot/Aset's blood

Flipping through my Egyptian books, I stumbled upon some curious connections between Aset (Isis), her blood, and red jasper. It seems to be a important protective stone. So when I got back online I looked up further information.

I found the tit(Tyet, Tet, Tyt,Tiet, Tjet) amulet of Isis.

The British Museum reports:

"From Egypt
New Kingdom, about 1250-1100 BC

The protection of Isis

The tit amulet was one of several which was placed on the neck of the deceased at the time of burial. It is first mentioned in funerary papyri and first appears on mummies in the mid-Eighteenth Dynasty (about 1550-1295 BC). From then on it was considered vital.

This example is made of red jasper, as prescribed in the Book of the Dead, though many examples were of other red materials such as glass or carnelian. Some were also made of green faience or glass. In ancient Egypt, green was symbolic of regeneration. The amulet was linked with the goddess Isis, and also known as the knot-amulet or girdle of Isis. It consists of a loop of cloth, from the tied lower end of which hung two folded loops. It may represent a cloth used during menstruation.

According to Spell 156 of the Book of the Dead the amulet bestowed the protection of Isis against 'whoever would commit a crime against him'. The spell, invoking the goddess' blood, power, and magic, was to be recited over the amulet, which was moistened with the juice of various fruit. This example is inscribed with Nefer's name, to ensure that the spell would be specifically applied to him."

You'll notice the shape of this knot is similar to a Ankh. Ancient Egypt online reports:

"The Tjet (Tyet, Tet, Tit, Tat, That, Thet) is also commonly known as the Isis knot, or Isis girdle. Some commentators have argued that the symbol was originally a variant of the Ankh. It has a similar appearance (except its 'arms' are bent downwards) and could also have a similar meaning, sometimes being translated as ' life'. As a hieroglyph it represented the Tjet amulet and the phonetic sound "s".

[...]

There is much debate regarding the subject of the symbol. It is similar to the knot used to tie garments in place, and so is often called the "knot of Isis". Knots were thought to bind magic, and so this would not seem to be an unreasonable suggestion. However, other commentators have suggested that it should really be 'the girdle of Isis' or 'the blood of Isis' as the symbol represents a female sanitary cloth used during menstruation or an ancient charm to help women deal with menstrual cramps. Others suggest it represents the female reproductive organs and represents Isis in her role as the universal mother.

While we cannot be certain of the original meaning of the symbol, there seems to be a link to blood, power and regeneration. The Book of the Dead states that a Tjet amulet should be formed from a red stone (such as carnelian, red jasper or red glass) and buried with the mummy. According to this ancient text - "The blood of Isis, the spells of Isis, the magical words of Isis shall keep this great one strong, and shall protect him from whosoever would harm him". However, the Tjet was not always red. Tutankhamun was buried with a beautiful blue Tjet and amulets were also fashioned from yellow sycamore wood (as the tree was sacred to Nut, Isis, and Hathor)."