"Brecciated" is the term used for a sedimentary mineral that has been broken apart and rejoined by a different mineral (often quartz). The effect is that of a natural mosaic, which gives a special charm to pieces with these minerals.
This necklace is two strands of brecciated mookaite with a lovely, heart-shaped pendant of the same mineral on a sterling bail. The extender chain allow you to adjust the necklace's length up to two inches longer.