Quartz Pseudomorph from Coromandel, New Zealand

A quartz after calcite pseudomorph occurs when quartz replaces calcite crystals, preserving their original shape. 

This particular one is from Coromandel, New Zealand. It has also been through an acid bath process to bring out the white colour. This has also given it more of an etched look than usual, giving it an almost coral-type look. 
Measurements are Approximate

8cm x 6.3cm x 3.8cm