This matrix specimen hosts a centered cluster, 3.7 cm across, of what looks like melted globules of glass but are in fact rounded GEM growths of a rare form of hyalite opal! These stunning gemmy yellow opals are from a modern find in Mexico, starting in around 2018, that produced material for both specimens and jewelry rough. The cut stones and gems from this material shine like yellow glass in interior light, but they start glowing in any sunlight, and turn neon green. This "DayGlo" effect is due to very trace elements of radioactivity within that cause intense fluorescence when activated by UV light (which is present in sunlight). So, earrings made out of this opal start glowing green when you walk outside. Specimens, as well!