In general a feather will be planar (two dimensional) in nature; much more visible when viewed from a position perpendicular to the feather's plane and almost invisible when line of sight is parallel to the plane. A crystal is typically more three dimensional in nature. It is often necessary to use much higher magnification than the 10X used to grade clarity, in order to determine the exact nature of an inclusion. Even then it takes a grader with a lot of experience to make fine distinctions. Usually it is not necessary to get to that level of detail in order to make a grading call. Of course researchers live for making such distinctions and sleuthing out the exact nature of the minerals trapped inside diamonds.thecat|1438963694|3912179 said:non surfacing reaching feather? For educational purpose. Thank you![]()
thecat|1438963694|3912179 said:non surfacing reaching feather? For educational purpose. Thank you![]()
Wink|1438981292|3912304 said:thecat|1438963694|3912179 said:non surfacing reaching feather? For educational purpose. Thank you![]()
Are you talking about looking at the paper or at the diamond?
Wink
Texas Leaguer|1438975834|3912262 said:In general a feather will be planar (two dimensional) in nature; much more visible when viewed from a position perpendicular to the feather's plane and almost invisible when line of sight is parallel to the plane. A crystal is typically more three dimensional in nature. It is often necessary to use much higher magnification than the 10X used to grade clarity, in order to determine the exact nature of an inclusion. Even then it takes a grader with a lot of experience to make fine distinctions. Usually it is not necessary to get to that level of detail in order to make a grading call. Of course researchers live for making such distinctions and sleuthing out the exact nature of the minerals trapped inside diamonds.thecat|1438963694|3912179 said:non surfacing reaching feather? For educational purpose. Thank you![]()
thecat|1438963694|3912179 said:non surfacing reaching feather? For educational purpose. Thank you![]()
Hawk,Diamond_Hawk|1439171580|3912840 said:thecat|1438963694|3912179 said:non surfacing reaching feather? For educational purpose. Thank you![]()
The info from Bryan and Wink is great stuff. What you are seeing is likely, in fact, a "non surface reaching feather" ...or is it? By literal definition, GIA has defined a feather as "a separation or break that reaches the surface..." In practice, however, this is not always the case. It can vary from grader to grader and lab to lab. I'm curious, Bryan and Wink, how often do you come across an inclusion called a feather that does not break the surface?
It's often very difficult to see, especially in a small feather, but if you mirror the facet you will usually see a very fine straight line where the feather reaches the surface. They are usually not "open" in the sense that you can see any air space. It is possible that the feather is completely enclosed within the diamond (healed), in which case the polish could be a perfect mirror on the surface of the facet indicating that the feather is not surface reaching.Pyramid|1439336984|3913521 said:Bryan when you say most feathers you have seen break the surface, is that the same as what people call an open feather or is that something different again?