colour change sapphire. whats yhe reasonable price to buy one?

[muddy sparx]

Whats the reasonable price to buy a 1.48gram (7 carats) colour change sapphire changes from violet purple to green to pinkish red under different lighting

 

[lovedogs]

Since we don't know whether this is a CC sapphire (and neither do you based on the previous post asking us to identify), it wouldn't be reasonable to guesstimate a fair price on it.

 

[voce]

That is a piece of rough. Most of us here buy gemstones after they have been cut, so you would have to reach out to someone who buys rough (i.e. a gem cutter) for your question to get answered.

 

[pwsg07]

This colour change is very rare for sapphire. Most of the colour change sapphires are from blue to purple

 

[muddy sparx]

Since we don't know whether this is a CC sapphire (and neither do you based on the previous post asking us to identify), it wouldn't be reasonable to guesstimate a fair price on it.

I tested it using a presidium gem test and it read as sapphire

 

[muddy sparx]

That is a piece of rough. Most of us here buy gemstones after they have been cut, so you would have to reach out to someone who buys rough (i.e. a gem cutter) for your question to get answered.

Do you have anyone in mind?

 

[muddy sparx]

This colour change is very rare for sapphire. Most of the colour change sapphires are from blue to purple

So do you think it might be valuable? If so, I might have to contact G.I.A for testing and certification

 

[muddy sparx]

Since we don't know whether this is a CC sapphire (and neither do you based on the previous post asking us to identify), it wouldn't be reasonable to guesstimate a fair price on it.

And about the previous post, I also tested the presumed alexandrite on the presidium tester and it read between tourmaline, that confused me because tourmalines specific gravity is 3.06 and the other stone came out as 3.7 so it clearly is not a tourmaline ....

 

[muddy sparx]

Do any of you guys know how alexandrite reads on a presidium gem tester? because it is not mentioned on the device

 

[Bron357]

Do any of you guys know how alexandrite reads on a presidium gem tester? because it is not mentioned on the device

It tests as upper range Spinel/ lower range topaz. Just remember that the Presidum cant differentiate between manmade and natural gems if the same chemical composition. It is only registering the thermal signature not if it’s “out of the ground vs made in a laboratory”
And when comes to valuing raw crystals, firstly a gem cutter has to determine the best size, clarity gem he/she can cut from the rough. It’s not uncommon to lose up to 50% of the rough weight to get a lovely finished gemstone. The only type of people likely to buy rough gems are gem cutters. They are the only ones with the experience to assess a gem.
So say you end up with a 3.5 carats sapphire, depending on its final appearance, cut quality and clarity it might be worth between $100 and $5,000 but if it’s included, zoned or with natural fissures, the cost of cutting could be almost equal to the value of the gem

 

[muddy sparx]

Thank you for the information

 

[muddy sparx]

It tests as upper range Spinel/ lower range topaz. Just remember that the Presidum cant differentiate between manmade and natural gems if the same chemical composition. It is only registering the thermal signature not if it’s “out of the ground vs made in a laboratory”
And when comes to valuing raw crystals, firstly a gem cutter has to determine the best size, clarity gem he/she can cut from the rough. It’s not uncommon to lose up to 50% of the rough weight to get a lovely finished gemstone. The only type of people likely to buy rough gems are gem cutters. They are the only ones with the experience to assess a gem.
So say you end up with a 3.5 carats sapphire, depending on its final appearance, cut quality and clarity it might be worth between $100 and $5,000 but if it’s included, zoned or with natural fissures, the cost of cutting could be almost equal to the value of the gem

I am thinking of testing the refractive index just to make sure, but it certain not a garnet because it passed the garnet section. These gemstones are confusing

 

[muddy sparx]

It tests as upper range Spinel/ lower range topaz. Just remember that the Presidum cant differentiate between manmade and natural gems if the same chemical composition. It is only registering the thermal signature not if it’s “out of the ground vs made in a laboratory”
And when comes to valuing raw crystals, firstly a gem cutter has to determine the best size, clarity gem he/she can cut from the rough. It’s not uncommon to lose up to 50% of the rough weight to get a lovely finished gemstone. The only type of people likely to buy rough gems are gem cutters. They are the only ones with the experience to assess a gem.
So say you end up with a 3.5 carats sapphire, depending on its final appearance, cut quality and clarity it might be worth between $100 and $5,000 but if it’s included, zoned or with natural fissures, the cost of cutting could be almost equal to the value of the gem

All my rough stones are torch passed. I don't buy stones which show inclusions to the naked eye, so I could say the stone is clean to the naked eye

 

[arglthesheep]

just test it with a rare earth magnet. So you normally could rule out garnet. Do you have a polariscope?

 

[muddy sparx]

just test it with a rare earth magnet. So you normally could rule out garnet. Do you have a polariscope?

No I don't have a polariscope, how do i test it with a earth magnet?

 

[arglthesheep]

Most of the garnets are magentical, so when you check it with the magnet you will know easily.
But please don´t take it as a 100 %, it is one big hint in the right direction.
Again I can link to the site, where you find very usefull information regarding this topic.
https://www.gemstonemagnetism.com/
Normally Corundum and spinel dont show any reaction with the magnet.