I call them cap ornaments because they have a cap on top of a sphere. Not a round cap like on a acorn, but a square cap. Turning from square stock with the aid of temporary joints gives the cap dramatic scallops.
The cap is hollowed using a template:
The cap can also be turned using a template:
You can turn a sphere for the cap using the shadow sphere jig or with a Template
After hollowing the top of the cap is turned using a cap drive:
Cap Drive for supporting the hollowed cap while turning the top.
Here are some samples showing the diversity of looks available by substituting various spheres the cap sits on:
A cherry cap over a maple ball.
A spalted ash cap on a shatterproof burgundy ball with gold glitter paint.
A spalted Ash cap and finial over a burgundy shatterproof ornament covered with silver mesh fabric.
A spalted ash cap and finial over a Styrofoam ball covered with white t-shirt and purple/silver mesh.
Spalted Ash cap and finial. The ball is Styrofoam covered with white T-shirt and purple mesh.
Detail of the finial. The brass wire runs through the ball and cap to become the hanger.
Spalted Ash cap mounted with a bamboo skewer dowel. The ball is Styrofoam covered with red T-short and purple/silver mesh.
Spalted Ash cap. The ball is Styrofoam covered with red T-shirt and glitter.
A spalted Ash cap. The ball is Styrofoam covered with a white/gold/iridescent fabric.
A cherry cap mounted on a Styrofoam ball covered with white gesso and big glitter.
A cherry cap glued to a glass ornament.
A collaborative effort. A cherry cap over a Styrofoam ball covered with fabric embroidered with mistletoe leaves.
A collaborative effort. A maple cap over a Styrofoam ball covered with quilted fabric.
A 3" maple ball with spalted ash cap.