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 Post subject: Change of colour after sieving
PostPosted: Wed Feb 01, 2012 5:34 am 
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I recently purchased a parcel of D-F coloured stars and melee. I sieved the parcels for the different sizes, only to discover (to my horror) that the colour had now changed to a silvery shade. That was not the case before i sieved the lot. Many years ago i had heard that there was a treatment being done in India where the parcel would remain white as long as you did'nt sieve.
Does anybody know anything about such a treatment or have an explanation? Please advise.


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 Post subject: Re: Change of colour after sieving
PostPosted: Wed Feb 01, 2012 7:56 am 
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first time i hear something like that!!! maybe you need to clean your diamonds again

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 Post subject: Re: Change of colour after sieving
PostPosted: Wed Feb 01, 2012 10:09 am 
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Or your sieve ... lol


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 Post subject: Re: Change of colour after sieving
PostPosted: Wed Feb 01, 2012 10:17 am 
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roshanravan wrote:
first time i hear something like that!!! maybe you need to clean your diamonds again


same here......
however, some dirt is very difficult to remove.... i remember my teacher was in trouble cos he changed the tweezers type to something more advanced and techy.... the result was the new tweezers leaved a metallic dirt on all the diamonds used for the course and it was VERY dificult to clean'em.... :?

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 Post subject: Re: Change of colour after sieving
PostPosted: Wed Feb 01, 2012 7:10 pm 
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Sounds like the diamonds abraded the sieves, leaving a residue.
Have you tried cleaning?


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 Post subject: Re: Change of colour after sieving
PostPosted: Thu Feb 02, 2012 1:43 am 
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Thank you all for your responses.
I immersed the parcel in CTC and left it over night. Came back and cleaned the lot, and VOILA, it was back to its original colour. So the story i had heard many years ago was a fallacy and that parcel probably required re-cleaning as well. You live and learn, i guess.
Thank you all once again


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 Post subject: Re: Change of colour after sieving
PostPosted: Thu Feb 02, 2012 5:06 am 
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glad your problem is solved, you sieves probably got oxidized or bad quality?

here some tips for cleaning diamonds that i have learned after all of these years.

for every clean up i use a lint free gem clothes and eyeglasses cleaning liquid for diamonds, its best for cleaning liquid for diamonds and it removes most of dirt.

if your diamond's dirt is very difficult to remove (or you have a big parcel to clean) you can use touchstone's acid (Nitric Acid solutions) and immerse diamonds in the acid then in immerse them in special solution with baking soda or sodium salt and water to neutral acid, and again depth diamonds in water then clean them with eyeglasses cleaning liquid and lint free gem clothes

of course you need protective gloves and three Glass Beakers for acid and water solutions and you should do the cleaning in a well ventilated area

i should remind you to be cautious and follow every safety procedures and environments when working with acids.

do not do cleaning with acids in home or show room of jewelry store. i can not be more vivid about working with acids. just be careful, we don't want any accidents

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 Post subject: Re: Change of colour after sieving
PostPosted: Thu Feb 02, 2012 5:18 am 
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Thank you Roshan
Your recommendations are noted and i will definately impliment them. And yes, you have been quite explicit regarding the dangers of working with acids.
I thank you once again.
All the best


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