I’ve posted great new amethyst specimens in this Indonesia Update (click here). Known as “grape amethyst”, these pieces feature beautiful groups of amethyst balls.
Originally referred to as “grape agate”, specimens were first found in the Mamuju area in 2015. These specimens are recovered from clay, in the spaces between the “pillows” in pillow lava.  Although they were first known as “grape agate”, they are not cryptocrystalline (and therefore are not agate) – they are balls of radiating crystalline quartz. When the find first came to market, there was a large amount of material, much of which was poor quality. With the passage of time, the diggers began to produce higher quality specimens. The recent article on this material in the Mineralogical Record (Nov-Dec. 2018) observes that the production of fine specimens is beginning to decline, although there are still a few very active teams working the deposits. The article speculates, based upon local sources, that all specimen mining of the pillow lava deposits will likely cease within the next three to four years. As with all mineral specimen localities, the ultimate accuracy of such speculation varies. In this case, the limited geographical extent of the known pillow lava deposits is a key factor.

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 12.4 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 10.0 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 11.4 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 8.1 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 7.7 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 7.1 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 8.3 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 5.7 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 6.8 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 4.0 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 3.9 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 3.8 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 4.0 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 4.3 cm

Quartz, var. Amethyst, Mamuju area, Sulawesi Barat Province, Sulawesi, Indonesia – 3.5 cm