Blue / pink / purple / etc Stones at Telegraph Point, NSW

[user 4485]

For what it's worth, I was also told the gemstones likely did not come out of the basalt. So there is no point smashing basalt stones with a sledge hammer to look for crystals inside. The gemstones might not even originate from the same event that caused the basalt (the basalt is hardened lava). At most all that can be said is that they are likely caused by the same hot spot that caused the basalt. The specific event that caused the gemstones to come to the surface could have origins that are thousands of years different to the event that caused the lava.

Just to clarify/expand on this a bit for people reading the thread.
I don't agree with what DeanMNC has been told here but yes going around smashing up basalt rocks would likely prove fruitless.
While gemstones can be contained in basalt, basalt is very hard & trying to retrieve gems from the rock would probably just break the gems anyway.

Corundum, (sapphire and ruby) forms deep in the Earth's crust and is brought to the surface in igneous rocks that are high in aluminium but low in silicon, such as basalts. Corundum is also found in rocks that have been metamorphosed. Source: Geoscience Australia

This area of basalt is weathered so IMO it's the weathered basalt that is the source & has allowed the gems to remain after weathering then become alluvial in the waterways with other gravels.

Economic sapphire and ruby deposits are only found when an igneous rock, such as basalt, is weathered and eroded away, leaving behind the tougher and more resistant minerals such as sapphires and rubies. These then become concentrated in certain parts of the landscape after being transported by rivers and streams (placer deposits). Most of the sapphires and rubies from eastern Australia occur in placer deposits. Source: Geoscience Australia

Ruby deposits are more uncommon as they depend on the presence of the rare element chromium. Ruby is usually found in metamorphic rocks, such as those in the Harts Range in the Northern Territory. However, a more transparent, gemstone-quality ruby comes from a few areas in eastern Australia where it has been brought up from underlying metamorphic rocks by volcanic action. Source: Geoscience Australia

 

[Heatho]

The larger blue stones do look quite like non gem quality corrundum/sapphire to me, one does actually look like a dogtooth sapphire crystal in one of the pics.
Quite hard to tell without decent photes and light underneath the stones.

The pinky red stones I'd say if one does flouresce then it's quite probably a ruby or pink sapphire. The others are possibly
Spessartite or Rhodolite garnets. They don't look like zircons to me.

I've never seen an Aussie ruby that doesn't flouresce.

Anyway all pics aren't really good enough to give a proper ID.

Interesting spot though, I'd keep looking to see what else pops up.

 

[Jaros]

G'day Heatho- great to see you on site again.

 

[Heatho]

G'day Jaros, yeah I drop in now and then. Hope you've been keeping well.

Cheers

 

[Dihusky]

The best UV for identifying Ruby is shortwave, picture is garnet vs ruby in the rough state.