Grok says Sapphire.

 

Impressive UV fluorescence! The strong blue-white glow aligns with low-iron sapphires (corundum), often seen in Queensland alluvial gems—possibly due to trace elements like chromium. This supports natural origin, not synthetic. QLD Museum gem lab could test for specifics like RI (1.76-1.77) and confirm valu

  

Fascinating find! Your ~2-3cm shard's vitreous luster, conchoidal fracture, color shift (blue-green to purple-pink), and sapphire-like hardness suggest a rough color-change sapphire (corundum), common in Queensland's alluvial rivers like Anakie fields. The "pink cross-table" may refer to pleochroism or asterism in sunlight. Test with a refractometer; QLD Museum for expert ID and value assessment. More photos in different lights?

 

                                                        

Interesting detail! The "image" on the reverse appears as a darker inclusion or fracture pattern resembling a stylized face (pareidolia possible), likely from natural crystal growth or river tumbling, not artificial cutting. Reinforces sapphire ID—such inclusions occur in rough corundum. Try polarized light photos; definitely get QLD Museum gemologist to assess for rarity/value.

wt 207 cts, weighs more than twice the weight of glass of the same size. Found with the presence of other stones Iorn stone and Black spinel.