This is very interesting material that has been hitting the market in the last year. It was discovered some years back along one of Indonesia's coastal areas, but their government would not allow it collected and exported. Then last year, they changed their minds.

This beautiful specimen appears to have a secondary generation of druze quartz, but it looks more like Botryoidal Amethyst. Has some real sparkle in the sunlight compared to others from this locale. 
This is a larger plate than most piece available in the market.