Clarity And Value Flashcards
What is the classic definition of clarity?
A gemstones relative freedom from inclusions and blemishes.
Aka purity, quality.
What is a plot?
A color-keyed diagram of a gemstone’s significant clarity characteristics.
It simplifies the task of finding a diamond’s clarity characteristics.
When can clarity characteristics appear?
During formation, during the cutting or setting process, or even when the diamond is worn
How does clarity relate to a diamond’s value?
The diamonds with no clarity characteristics are more rare and valuable.
What is a type of clarity characteristic that can occur during diamond formation?
Graining. Which is a development of irregularities in the crystal’s atomic structure.
Looks like faint lines or streaks and can parallel and or intersect.
What is the collective term for diamond cleavages and fractures?
Feather. They also have a white feathery appearance
What is a break?
A clarity characteristic that can develop during or after formation.
Either a cleavage or a fracture
What does a cleavage look like?
A break parallel to the weakest direction in the gem’s structure.
Sometimes has a step-like appearance.
What is a Fracture?
A fracture is a break in any other direction, I.e. Not parallel to the weakest direction of the gems structure.
Where can the most damaging breaks occur on a diamond?
The most damaging breaks occur along the weakest direction in the crystal structure, especially if those breaks pass through the girdle or occur near points or corners.
What are the five factors that determine the overall effect of characteristics on a clarity grade?
Size Number Position Nature Relief
Where is the “heart” of the diamond?
The area right under the table
Where are inclusions most visible in a stone?
When it is located right at the heart of the stone
What is a reflector in terms of clarity characteristics?
When an inclusion is located in the pavilion facets, causing it to look like many inclusions
What type of inclusion have the greatest impact on a diamond’s clarity grade?
Feathers. Especially when large and reaches the table or extend from the crown thru the girdle.
What does relief mean in clarity terms?
Visibility. Most inclusions are white or colourless, but can also be black, brown, dark red or green.
How can a cutter improve the clarity of a diamond?
By eliminating (cutting off) or hiding (positioning) clarity characteristics.
What does bruting mean?
Rounding up, or girdling. One of the first steps in the cutting process in which to form the basic face-up outline of the diamond to prepare it for faceting - can create clarity characteristics
How can a cutter demonstrate that they have retained maximum weight and diameter from the rough?
By leaving a part of the crystals original surface- natural - on the fashioned diamond
What is the difference between inclusions and blemishes?
Inclusions are within or extend from the surface in to the stone. While blemishes are limited to the surface.
What is a bearded girdle?
BG
An inclusion that is a very small feather extending from the girdle surface into the stone; can result from the cutting process.
What is a bruise?
Br
Inclusion. Tiny area of impact accompanied by very small, root-like feathers; typically occurs at a facet junction.
Cavity?
Cv
Inclusion. An angular opening created when part if a feather breaks away.
Chip?
Ch
An inclusion in which a shallow opening that occurs at a girdle edge, facet junction, or culet ; caused by damage tome stone’s surface.
What is a cloud?
Cld
An inclusion in which many tightly grouped pinpoints that might be too small to distinguish individually but together have a hazy appearance.
Feather?
Ftr
The general trade term for a break in a gemstone, often white and feathery in appearance.
What is the grain centre?
GrCnt
Inclusion. A small concentrated area of crystal distortion; can be white or dark, and might have a thread-like or pinpoint - like appearance.
Crystal?
Xtl
An inclusion in which a mineral crystal is contained in a diamond.
What is indented natural?
IndN. Inclusion
A portion of the rough’s original surface that dips below a polished diamond’s surface, or an opening left when a surface-reaching crystal drops out or is forced out during polishing.
What is meant by internal graining?
IntrGr. Inclusion
Lines, angles, or curves that might appear whitish, coloured, or, reflective, or affect transparency at 10x; caused by irregularities in crystal growth.
What is internal laser drilling?
ILD an inclusion in which a laser drilling within a diamond that doesn’t reach the surface.
What is a knot?
K
An inclusion in which a transparent included diamond crystal that extends to the surface after fashioning.
What is a laser drill hole ?
LDH inclusion.
A tiny surface-reaching tunnel produced by a laser light beam.
What is a needle?
Ndl. An inclusion in which a thin, elongated crystal that looks like a tiny rod at 10x
What is a pinpoint?
Pp. inclusion.
A very small crystal that looks like a tiny dot at 10X
What is a twinning wisp?
W
Inclusion
A series of pinpoints, clouds, or crystals that forms in a diamond’s growth plane; associated sigh crystal distortion and twinning planes.
What is an Abrasion?
Abr
Blemish. A series of minute nicks along the facet junctions of a fashioned diamond; gives the edges a white or fuzzy appearance
What is an extra facet?
Ef. Blemish.
A facet that’s nit required by the cutting style, place without regard for the diamond’s symmetry; mist often found near the girdle.
What is a lizard skin?
Blemish. Wavy or bumpy area on the surface of a polished diamond.
What is a natural?
Nk. Blemish.
A small notch on a facet junction with no readily apparent depth at 10x, usually along the girdle edge or at the culet.
What is a pit?
Pit. Blemish
A small opening that looks like a tiny white dot
What are Polish Lines?
PL . Blemish
Fine parallel grooves and ridges left by polishing; can occur on any facet but do not cross facet junctions; transparent or white.
What are burn marks?
Brn. Blemish
Hazy surface area that results from excessive heat or from uneven polishing caused by structural irregularities; also called polish mark or burned facet.
What is rough girdle?
RG
a blemish that is caused by irregular granular girdle surface
What is a scratch?
S.
Blemish caused by a thin, dull line across the diamond’s surface; shows no apparent depth at 10X
What is surface graining?
SGr
A blemish similar to internal graining except, Except it appears on the surface results; from irregularities in crystal structure
What is the laser drilling
Laser drilling is a treatment that involves using a concentrated beam of laser light to reach a diamond’s dark inclusions and to disguise and eliminate them.
What is fracture filling?
Fracture filling is a treatment that involves injecting a molten glass substance into a diamond’s surface-reaching feathers or laser-drill holes
What does apparent clarity mean?
A term used to describe the effects of treatments on the visual appeal of a gemstone
What are the clarity treatments that can improve a diamond’s clarity?
Laser drilling and fracture filling
How does fracture filling work to improve a diamond’s aparent clarity?
Fracture filling works because the filling material has a refractive index RI that’s closer to diamonds RI than to air’s RI.
The fillings RI makes light behave almost as if it were passing through diamond.
What is RI? What is the RI of a diamond? What is the RI of air?
Refractive index. Diamonds RI is 2.417 air is 1.000
It is a measure of a material’s ability to bend and slow light.
What is a necessary disclose when a diamond has been treated with diamond filling?
That it improves the apparent clarity of the stone, it doesn’t heal it or make it go away.
