Witchy Tools: Athame/Knife
Athames are a specific style of ritual knife that are primarily used in Wicca, but have also spread to wider witchcraft. However, if a witch does not have access to a dedicated athame, a regular knife can also be used for a similar purpose. The use of a blade in the craft is primarily for directing energy and magical workings: by casting a circle, calling elements, binding or severing magical attachments, and more. It is traditionally associated with the element of fire, and the magical energies of creation, destruction, and transformation.
A dagger with a black handle and an iron blade (traditional)
A knife (general or modern)
Ink or a tool for carving (optional)
The only universal process of using a blade in a ritual is consecrating it in whatever tradition you follow, to elevate it above the mundane for the duration of the ritual. Beyond that, you can also choose to ink/carve runes or symbols onto the handle of the blade if you want to use it for a specific purpose and enhance those qualities of it. Again, the runes and symbols can belong to whichever tradition you follow, as there are traditional ones to certain paths and self-created ones in others.
Blades have been used ritually since ancient times - often for important cultural ceremonies or religious events. There is also a strong overlap between some parts of early religion and what many would consider now to be modern witchcraft, making it difficult to tell when one separated from the context of the other. However, the athame in particular dates back to the Key of Solomon grimoire from the 14th-15th centuries (the official date is contested). There is some translation disagreement about what kind of blade it specifies, however it has become a common tool of the modern witch and Wiccan nonetheless.