Can an avocado seed be ink?

Question

Can an avocado seed be ink?

Answer 1

The seed of avocado contains a milky fluid holding tannin. If you open this hard and heavy "stone", the inner fleshy substance  comes in contact with oxygen and light and turns red, excreting a red-brown or blackish ink which was used to write many documents in the days of the Spanish Conquest.  

The ink has also been used to mark cotton and linen textiles.

Answer 2

An avocado doesn't have a seed (seeds are small things) it has a ruddy great big stone!

As for ink from it - where did you get that notion from (genuinely curious)?