Finding and Identifying Clarity Characteristics (Chapter 10, Key Terms, Key Concepts, & Diamond Clarity Characteristics) Flashcards
Clarity characteristic that’s
confined to the surface of a polished
gemstone
Blemish
Internal or external
feature of a gemstone that helps determine
its quality and establish its identity
Clarity characteristic
Lighting of a diamond from the side against a black,
non-reflective background.
Darkfield illumination
The distance that’s clear
and sharp above and below a point you
focus on with a magnifier.
Depth of field
A position that orients a gemstone’s crown facets and table toward the
viewer.
Face-up
A trade term for any break in a
diamond.
Feather
A flash of changing color
seen in a fracture-filled diamond when you
look parallel to the filled inclusion and rock
the diamond back and forth under magnification.
Flash effect
Treatment that involves
injecting a molten glass substance into a
diamond’s surface-reaching feathers or
laser drill-holes.
Fracture filling
Clarity characteristic totally
enclosed in a polished gemstone or
extending into it from the surface.
Inclusion
Clarity grading is one of the most important
aspects of the GIA Diamond Grading System
Key Concept
Clarity characteristics determine a stone’s clarity
grade, help set its value, and help identify it
Key Concept
Your first impression of a diamond’s face-up
appearance should strongly influence its clarity
grade
Key Concept
Accurate clarity grading depends on a careful and
systematic examination of the diamond.
Key Concept
If a trained grader can’t see a clarity characteristic
at 10X, it doesn’t affect the clarity grade.
Key Concept
Use abbreviations to note inclusions and
blemishes.
Key Concept
You must disclose the presence of laser drilling
Key Concept
A natural can be considered a sign of efficient
cutting.
Key Concept
A mineral crystal contained in a diamond.
Crystal (Xtl) (INTERNAL INCLUSIONS)
A long, thin crystal that looks like a tiny rod at 10X
Needle (Ndl) (INTERNAL INCLUSIONS)
A very small included crystal that looks like a tiny dot at 10X
Pinpoint (Pp) (INTERNAL INCLUSIONS)
Many tightly grouped pinpoints that might be too small to
distinguish individually at 10X but together have a hazy appearance.
Cloud (Cld) (INTERNAL INCLUSIONS)
A series of pinpoints, clouds, or crystals that forms
in a diamond’s growth plane; associated with crystal distortion and twinning
planes
Twinning Wisp (TW) (INTERNAL INCLUSIONS RESULTING FROM CRYSTAL STRUCTURE)
Lines, angles, or curves that might appear whitish,
colored, or reflective or affect transparency at 10X; caused by irregularities
in crystal growth
Internal Graining (IG) (INTERNAL INCLUSIONS RESULTING FROM CRYSTAL STRUCTURE)
A type of internal graining that consists of a small,
concentrated area of crystal distortion; can be white or dark, and might
appear thread-like or pinpoint-like.
Grain Center (GC) (INTERNAL INCLUSIONS RESULTING FROM CRYSTAL STRUCTURE)
General trade term for a break in a gemstone. Often white
and feathery in appearance.
Feather (Ftr) (SURFACE-REACHING INCLUSIONS)
An angular opening that starts at the surface and
extends into the stone, often with striations perpendicular to its length.
Etch Channel (EC) (SURFACE-REACHING INCLUSIONS)
Minute or minor feathers that run perpendicular to
a bruted girdle; referred to more generally as feathers in the girdle.
Bearded Girdle (BG) (SURFACE-REACHING INCLUSIONS)
A tiny area of impact accompanied by very small, root-like
feathers visible at 10X magnification; typically occurs at a facet junction.
Bruise (Br) (SURFACE-REACHING INCLUSIONS)
An included diamond crystal that extends to the surface after
fashioning.
Knot (K) (SURFACE-REACHING INCLUSIONS)
Naturally occurring radiation stain left on a
polished diamond. Typically a blemish, but can be an inclusion if it extends
into the stone when viewed at 10X.
Patch of Color (Patch) (SURFACE-REACHING INCLUSIONS)
A shallow opening caused by damage to the stone’s surface;
typically occurs at a girdle edge, facet junction, or culet.
Chip (Ch) (SURFACE-REACHING INCLUSIONS)
An opening on the surface that occurs when part of a feather
breaks away, or when a crystal drops out or is forced out, typically during
polishing
Cavity (Cav) (SURFACE-REACHING INCLUSIONS)
A portion of the rough’s original surface, or skin,
that dips below the polished diamond’s surface at 10X.
Indented Natural (IN) (SURFACE-REACHING INCLUSIONS)
A tiny, surface-reaching tunnel produced by a laser
light beam.
Laser Drill-Hole (LDH) (INCLUSIONS CAUSED BY TREATMENT)
Laser drilling within a diamond that doesn’t
reach the surface.
Internal Laser Drilling (ILD) (INCLUSIONS CAUSED BY TREATMENT)
A small notch on a facet junction with no readily apparent depth
at 10X, usually along the girdle edge or at the culet.
Nick (Nck) (BLEMISHES CAUSED BY WEAR)
A series of minute scratches or pits along the facet junctions
of a fashioned diamond; gives the edges a white or fuzzy appearance.
Abrasion (Abr) (BLEMISHES CAUSED BY WEAR)
A thin, dull white line across the diamond’s surface; shows
no apparent depth at 10X.
Scratch (Scr) (BLEMISHES CAUSED BY WEAR)
A small facet that’s not required by the cutting style,
placed without regard for the diamond’s symmetry; most often found near
the girdle.
Extra Facet (EF) (BLEMISHES INTRODUCED IN THE CUTTING PROCESS)
A feature that resembles an extra facet but lacks a distinct
or straight facet junction
Polish Mark (BLEMISHES INTRODUCED IN THE CUTTING PROCESS)
Wavy or bumpy area on the surface of a polished
diamond.
Lizard Skin (LS) (BLEMISHES INTRODUCED IN THE CUTTING PROCESS)
Fine, parallel grooves and ridges left by polishing; can
occur on any facet but do not cross facet junctions; transparent or white.
Polish Lines (PL) (BLEMISHES INTRODUCED IN THE CUTTING PROCESS)
Hazy surface area that results from excessive heat during
polishing or occasionally from a jeweler’s torch.
Burn (Brn) (BLEMISHES INTRODUCED IN THE CUTTING PROCESS)
A surface burn caused by excessive heat at the location
where the dop touches the diamond.
Dop Burn (Dop) (BLEMISHES INTRODUCED IN THE CUTTING PROCESS)
Irregular, pitted, or granular surface of a bruted girdle.
Rough Girdle (RG) (BLEMISHES INTRODUCED IN THE CUTTING PROCESS)
A small opening that looks like a tiny white dot at 10X.
Pit (Pit) (BLEMISHES INTRODUCED IN THE CUTTING PROCESS)
A portion of the original surface, or skin, of a rough diamond
left on a fashioned stone; usually on or near the girdle.
Natural (N) (BLEMISHES RESULTING FROM CRYSTAL STRUCTURE)
Similar to internal graining, except it appears on
the surface; results from irregularities in the crystal structure.
Surface Graining (SG) (BLEMISHES RESULTING FROM CRYSTAL STRUCTURE)
The inclusion called bearding consists of tiny
feathers.
Which of the following is classified as an inclusion?
chip.
Which of the following is not a diamond inclusion?
Gas bubble
An example of a blemish is an
natural.
Inclusions are easier to see using
darkfield illumination.
A loupe used for clarity grading must be corrected for chromatic and
spherical distortion.
A surface indentation with tiny, root-like feathers penetrating the stone is called a
bruise.
An included diamond crystal that extends to the surface of a fashioned diamond is called a
knot.
Trigons are
growth marks.
A portion of the rough’s original surface, or skin, that dips below the polished diamond’s surface is called a(n)
indented natural.
A clarity characteristic confined to the surface of a polished gemstone is called a(n)
blemish.
A solid mineral body enclosed within a diamond (or other gem) is
an included crystal.
A “paper-worn” diamond is one that has
abrasions.
With darkfield illumination, light is directed into the stone from
the side. (against a black, non-reflective background)
A term used to describe any break within a diamond is
feather.
