Knot in table of MRB - opinions please!!

[can24]

Hi All - I'm looking at a MRB that has a large knot inclusion.

This stone is XXX, HCA of 1.5, VS2, idealscope is below.



Is a knot a deal breaker?

This is a close up of the table, see if you can spot the knot!

 

[ringo865]

It'll hardly be a "large" inclusion if it's a VS stone. Did the vendor say it is clean? What are the other specs (table, crown, PA, etc)?

 

[can24]

Vendor says it's clean!

57 table
62 depth
34 CA
41PA

 

[bmfang]

It's hard to spot to my eyes at that magnification. Will be even harder to see at normal viewing distances or even with a loupe.

Specs checkout with hca as well (score of 1.5)

 

[can24]

Ok, well, I think the plot looks like it's huge!

 

[whitewave]

It looks huge, but it is one of several inclusions, so it's not a big deal. It's still a VS2; if it was the only inclusion on a SI1 stone, you would have to look at it more.

This wouldn't bother me. I give my blessing

 

[ringo865]

That, and if the vendor has a good return policy (14-30 days, no restocking fee, etc.), then it's worth a look - get it and see it in person.

 

[Karl_K]

knots on the crown are a no no to me.
They can be dislodged and reduce the clarity grade of the diamond by a lot.
For a one of a kind very special diamond maybe I would consider it but for a common type.. naw not worth the potential problems.

 

[can24]

Thanks Karl! I'm leaning your direction on this stone, but I want to know if you've seen/heard the knot being dislodged before? I don't really understand how that would happen/what that would look like! A gaping hole? nothing? I would love to be educated on this!

 

[whitewave]

Ooh, I defer very obviously to Karl. If he says no, its a no.

 

[Karl_K]

Thanks Karl! I'm leaning your direction on this stone, but I want to know if you've seen/heard the knot being dislodged before? I don't really understand how that would happen/what that would look like! A gaping hole? nothing? I would love to be educated on this!

Yes, I have heard of it and seen it.
It can leave a hole that can be several times larger than the knot and quickly fills with gunk. It can easily take a diamond from vs/si to I1-13 clarity.
Some knots are more secure than others of course but is it really worth the chance?

 

[can24]

Nope! You're right!

 

[bmfang]

Karl, just out of curiosity, how would a knot become dislodged during daily wear?

 

[Karl_K]

Karl, just out of curiosity, how would a knot become dislodged during daily wear?

lots of different ways.
Remember diamond is hard but it is also brittle.
A diamond on a finger is always getting knocked, pushed and pulled.
Even getting some water under it then a rapid change in thermals could potentially pop it out.
More likely the thin edges holding it in chip off over time until it gets loose and comes out.

I am betting that if you put a sensor where the diamonds table is that counts contacts every time it touches something it would add up to thousands of times a day on average.

 

[bmfang]

lots of different ways.
Remember diamond is hard but it is also brittle.
A diamond on a finger is always getting knocked, pushed and pulled.
Even getting some water under it then a rapid change in thermals could potentially pop it out.
More likely the thin edges holding it in chip off over time until it gets loose and comes out.

I am betting that if you put a sensor where the diamonds table is that counts contacts every time it touches something it would add up to thousands of times a day on average.

Ah ok. Never thought to consider rapid temperature fluctuations as a potential cause of a dislodgement.

The couple of recent threads where posters have looked at stones with knots in them has been a bit of a refresher course for me on this type of inclusion. So used to only really seeing pinpoints, crystals (which is essentially what a knot is, just closer to the surface of a facet), needles and clouds as the main types of inclusions we're asked to comment on in stones.

I think your second sentence is something that a lot of us (myself included) forget. Yes it may have a hardness rating of 10 on the Mohs scale, but diamond can be cleaved with a sharp strike at a weak spot (hence its brittleness).