Michael's Martinuzzi dolphins post has inspired me to show this bowl. Both lovely and such very different items, only separated by two or three decades.

This alabastro geode is 16cm in diameter, 4cm high and heavy at 2kg. The alabastro/amethyst/alebastro combination produces striking visual effects.
This colour combo can be seen in a different geode bowl (top left) on page 77 in Archimede Seguso Lace & Stone by Leslie Pina, several bowls with the same form on page 80.
John