Step 1:
Take a small paper square and fold it in half.

Step 6:
Fold the model in half over the white line and fold the upper center downwards over the blue lines.
I folded my shark tooth around a silver necklace (see arrows).

Step 5:
Fold these prefolded lines into the other direction

Step 3:
Make the same folds on the backside.

Step 2:
Fold in half

Step 4:
Prefold the model and open it afterwards.

Step 7:
Fold on the two upper corners and glue both parts together at the bottom.

Done!
This is a DIY video tutorial for folding the Shark Tooth:

Origami Shark Tooth Necklace
DIY video for making a paper Shark Tooth on a necklace. The shark tooth is folded out of a small black paper. pic.twitter.com/MIloKKweq9

— Joost Langeveld (@LangeveldJoost) February 15, 2020

Picture: Origami Shark Tooth on a silver necklace