The thundereggs were known some time ago and they were in Peter Ghitney's old collection, but they had been mislabelled as "Ascension thundereggs".  Alberta Del Ray by chance re-discovered the exact same thundereggs at Casas Grandas, Mexico and I suggested "Lilac Thundereggs" since the color of agates are similar to the lilac flowers. The thunderegg's rhyolitc shells are reddish with oolitic-like texture on the rough surfaces while the ridges are usually difficult to make out on the surface. The agate cores tend to be narrow and the typical colors are gray to lavender. The agates with deep purple, pink, orange, red and black had been found and few ones came with plume inclusions.