Defining what is a CAVITY

[in_need_of_help]

Interesting findings.

I looked for "cavity diamond" on Yahoo and found different definitions at different websites.

Some say that a cavity in an inclusion, that it is inside of the diamond. FYI, GIA states that a cavity is an inclusion.

Others say that a cavity is a blemish, that it is on the surface of the diamond.

Any thoughts?

In_need_of_help

 

[oldminer]

A cavity is a BIG blemish and definitely an inclusion. A normal blemish may be removed with light polishing, in general. An inclusion might be removed with re-polishing or recutting, but an inclusion might be too deep or too large to remove by any method. A cavity may fall into the category of removeable and in might not because of depth or size.

Sometimes an inclusion can be removed by recutting, but financial considerations might well dictate the value is greater with an inclusion and the extra weight, than without the inclusion and the lessened weight.

That is only part of what makes the diamond business interesting. It is not 100% the same for every instance. It takes calculations, brain power, skill, knowledge and luck, too.

 

[Mara]

Here are some threads on cavities...though not too much information.






https://www.pricescope.com/community/threads/bobs-flashes-cavity-in-diamonds.6368/




https://www.pricescope.com/community/threads/what-is-a-cavity-on-a-diamond.4854/




Question for the experts:




If a cavity is along a girdle and settable under a prong....are there ANY negatives to purchasing that stone (assuming cut, color etc is all great)? For example, will the cavity be safe under a prong, or will it have chances of widening or somehow impacting the stone at all? Or basically once it is set....it's forgotten?

 

[mdx]

Here is quiet an accurate definition of a cavity.

Cavities are natural surface indentations or nicks, fracture cracks and damage occurring outside the diamond and expanding towards the inside. They also include holes in the surface caused by crystal inclusions falling out during cutting. This creates a hollowed out effect. To remove cavities usually results in relatively high weight loss so they are often left to be taken into account in grading.

Some years back I saw a diamond that after cutting had a carbon inclusion very close to the surface but was not open. After a few years wear the owner bumped the diamond on the inclusion area breaking the thin skin, the carbon came out leaving a cavity, unfortunately on the table.

Like Dave says this is certainly and interesting Industry

Wayne
Melbourne Diamond Exchange Ltd. (Australia)

 

[diamonddee]

I am looking for help from the experts. My husband and I are about to purchase a 3 stone diamond ring. It has 1.75 ct tw. The center stone is 1.01 ct. Set in platinum. The problem is that the center stone has a cavity close to where the progs are. The ring is appraised for $7,000+. We are purchasing it for $4,700 on sale. I am concerned about the cavity. I have never heard of this term before. I cant see any visible holes. It comes with a GIA cert. color-H, clarity- SI2. What do you think?

 

[Rhino]

A cavity in an SI2 graded diamond is something YOU SHOULD NOT PURSUE UNLESS YOU HAVE IT CHECKED BY A PRO. It could be a cause for future problems and headaches. I would make the sale contingent upon an expert analysis. Consider some of the appraisers who participate here like Dave Atlas, NE Gem Lab, Rich Sherwood or RockDoc to help you out and possibly avoid a future headache.




Rhino

 

[pyramid]

I believe I read somewhere that if a cavity is the result of a crystal which was pulled out during polishing then the cavity wall will effectively be sealed and therefore no further damage can occur. Perhaps an expert can comment if this is the case?

 

[pyramid]

=

 

[dimonbob]

A cavity can be very very small and only visible under a jewelers loupe and others can be big enough to put something larger than a match head into. A cavity is not likely to expand or collapse. The real problem with a cavity under a prong is the cavity will collect dirt and it is difficult to clean out when under a prong.