Star Sapphire Rough

[Gilly47]

Hello ALL, having trouble identifying star sapphire in the rough, have searched a number of sites and am none the wiser.

most of the info i see is . a star saph exhibits a asterix pattern when viewed down the c axis.

does anyone have a pix of such a stone please.

struggling to understand the info as stated ATM

waiting in anticipation ray

:gemstone: :gemstone: :bomb: :bomb: :100: oop: oop:

51 carat found at reward cq, covers most of a 1$ coin

 

[Gilly47]

looking for any info please

ray layful:

 

[Wally69]

Yummy yellow sapphire there Ray :inlove:

I think it is all about the silk when it comes to stars, not sure if you have come across a grey silky stone yet, they are probably the best natural stones to educate yourself.

This is lifted from the www. But it shows the silky grey quite well.

Silk within a nice coloured sapphire, such as yours, may be able to be heat treated to reduce visible silk and brighten a stone.
With yours I would be cleaning it up on a lap to remove obvious faults and inspecting the silk closely.

Can it be avoided, can it be heat treated would be the first questions I would ask.......Then could it be cabbed, and if so what orientation may produce a star.

This image comes from an ancient text, but is quite enlightening.

 

[Wally69]

These all have stars, not fantastic, you will notice they are solid coloured stones (opaque), some with defined crystal banding colours.

The monotone blue, black and grey sapphires stones star up well but are cut slightly off axis, where the rubies are on axis but the star is confused by the colour banding.

The stone at the back shows a silky sheen to the surface and has been my indicator for having a play with a star.
It is a bit of a shitty photo, but I hope it helps.

 

[Heatho]

The copper coloured stones too are ones that should cut a decent star sapphire as well. As Wally said on rough stars you can see a different type of sheen to them when you move them around under a light source.

The stone in the centre on this pic is a 50ct one my mate found at Inverell, it's mainly black but has the copper colour on top. It hasn't been cut so I don't know whether it will star or not but it should.

 

[Martyz]

Hey Gilly,
I recently bought a bag of concentrate from Rubyvale and got this out of it. Im hoping it is a star. At just the right position with my iPhone as backlight I can pick up this star shadow. This shot is of the rough stone so maybe it will help.

 

[Wally69]

Have a look halfway down this page for a couple more examples, the star is created by light concentrated into rays, appearing as a bright but thin lined star.

https://www.prospectingaustralia.com/forum/viewtopic.php?id=1685&p=17

Martyz; your stone shows a natural crystal multi-colour pattern, the star wagon wheel (trapishe) effect looks awesome on some stones by skin polishing and setting into a pendant setting, particularly if the light catches the lighter colours. Yours shows good promise due to the bright yellow matrix.

 

[Martyz]

Cheers Wally. I like the look of those so Im excited to see the polished result when get to it.
Gilly, at least you know this isnt what youre looking for in a star.

 

[Gilly47]

Many thanks Peeps

Robyn has split a trapiche and made 3 pendants for her close friends.

The blue trapiche shown here looks GR8.

we now understand what to look for in a star rough, and its orientation

ray

:gemstone: :gemstone: :gemstone: R GR8