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Key to Understanding Descriptions Used

To understand how AMR Previewers examine jewelry and how AMR describes this process, please be aware of the following.

Jewelry is examined at auction galleries under "as is" conditions, using available lighting. At times, the Ott light is brought to the preview because it affords a neutral lighting environment (5000K). Jewelry may not be completely clean; stones described are observed in their mountings. Because of this difference between examining gems and jewelry under laboratory conditions and under auction conditions, AMR likens its descriptions to "Desktop Gemology."

We describe material in every day language and make comparisons to similar lab terminology. We assume that gemstone treatments (for color or clarity enhancement) have occurred as customary in gem processing procedures, unless accompanied by a gem lab report indicating otherwise.

We also describe the examination conditions. Because the auction area is not a laboratory environment, we use broad descriptive terms, as illustrated in the charts which follow.

For each item, AMR provides the following information:

Such description, combined with photos, enables you to better envision the piece you are researching.

Here's an example of our data...


Terms used in the Condition field are defined as follows:

NOTE: These definitions apply to all jewelry periods. However, the marketplace is harsher on modern pieces with excessive wear than on antique or period items in similar condition.

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Color Communication for Diamonds

There are two sets of diamond color grading criteria:

For those stones which are judged for absence of color we use the following terms:

White, Off White, and Some Color (yellow or brown) VISIBLE IN THE FACE UP POSITION.

The gems which the trade generally labels as "fancy" colors are described using the GemDialogue color saturation scales for physical comparison. Those of you who have the GemDialogue System will be able to visualize, the actual saturation level of the stone. For further information about GemDialogue, contact Howard Rubin at Auction Market Resource.

The following chart compares AMR's Desktop Gemology terms with those generally used in the trade labs:

AMR Color Terms Lab Comparison AMR Description Lab Description
White (Colorless) D, E, F Appears colorless to the naked eye Appears colorless when matched against master set
Off White (Nearly Colorless) G, H, I Nearly colorless to naked eye. Very slight tints of yellow or brown visible Slight color when matched against master stones
Some Color
(Yellowish or Brownish)
J to Z Slight color tints easily seen by eye in the face up position. Color tints match master stones with same colors.
Prominent Color Fancy light, fancy or fancy intense, fancy dark, fancy deep, fancy vivid. Prominent colors in the face up position are matched against the colors of the GemDialogue color charts. These are used as a master color set. Over 60,000 colors can be seen and matched against. Color terms vary with examiner. No comprehensive master set has as yet been accepted on an industry wide basis.


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Colored Stone Description

Color, in gemstones and diamonds, is described using the GemDialogue color saturation scales. Each chart shows 10 different saturation levels from strong to weak. If a stone has good color but faces up somewhat dark (due to blackish or brownish tones) then gray or brown scales will be added to the description. These are called masks and serve to simulate such face up appearance. All charts in the system are transparent and may be combined when necessary.

The GemDialogue verbal description breaks down the color into two primary parts:

A third segment precedes this description if a color mask is used (i.e., slightly, moderately dark, or very dark, moderate purplish blue with light, moderate or strong saturation).

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Due to the limiting conditions of examination by AMR preview associates at the auction galleries, AMR does not apply the GIA standard grading system for clarity grading. AMR evaluators judge how visible the inclusions are to the eye AND how visible they are with a loupe (10X power) on the following scale:

AMR Description Approximate Lab Description By Eye With Loupe
VVS (Internally flawless will only be used if accompanied by a lab report) Internally flawless, VVS1-2 Not visible by eye Absent, or very difficult to see with a loupe
VS May include lab VS grade and some SI1 inclusions not seen in the center Not eye visible Still difficult to find with loupe
SI Includes SI-1 & 2 grades Not eye visible Seen easily with loupe
I Includes all I lab grades Visible to easily visible to the eye Seen easily with loupe. Prominent inclusions seen by eye and loupe. Extremely obvious inclusion will also be mentioned under "Notes."

NOTE: These clarity terms will be used for both diamonds and colored stones. If a lab certificate accompanies the stone, the lab description will be provided, along with the previewer's notes, if not in agreement.

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Cut Grade

The eye appearance of the stone is a strong indication of how well the stone is cut.

Cut Grade Definition
Excellent Even color face up with no window, excellent symmetry and meeting of facets
Very Good Even color face up, very good symmetry and facets meet fairly well
Good May show small window, symmetry slightly off and facets do not quite align properly
Fair May show larger window, culet off center, facets unevenly distributed. Windows in colored gem material will show a different saturation level than the rest of the stone. The GemDialogue colors for the window and the perimeter will be noted if markedly different.
Poor May show large window, table and/or culet off center and uneven or missing facets

NOTE: Chips and scratches are addressed under "Notes."

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Polish Description

Describes the surface characteristics of a gemstone

Excellent No scratches, abraded facets, or polishing marks present.
Very Good No scratches, but some polishing marks and/or very slightly abraded facets present. Seen with difficulty by eye.
Good Slight scratches present and/or slightly abraded facets and/or polishing marks. Seen by eye but not in a prominent position.
Fair Worn material, but may be repolished — more prominent scratches, abraded facets, and polishing marks. Seen easily by eye in the face up position.
Poor Very worn material, needs recut — very prominent combination of scratches, abraded facets, and polishing. Seen very easily by eye, face up. Borders on damage instead of scratches and abrasions.

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Describes the degree to which the interior of a gem may be examined in the face up position, determined by the amount of light the gem allows to pass through it.

Transparent (TP) Allows an unobstructed view of the interior of the stone, face up, from table to culet
Transparent to translucent (TP-TL) Allows a slightly obstructed view of the interior of the stone, but the table and culet may still be seen in the face up position.
Translucent (TL) Here we begin to see a more obstructed view of the stone's interior. Surface or near surface inclusions may be examined from the top, but inclusions near the culet require the stone to be examined from the back.
Translucent to opaque (TL-OP) Allows some passage of light through the interior of the stone, but the view is too obstructed to allow a proper examination of the interior.
Opaque (OP) No light passes through the stone and no examination of the interior is possible.

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AMR determines that brilliance is a combination of both transparency and cutting and that if all other factors are equal, highly saturated material will always appear less brilliant than lightly saturated material. Since we already describe the cutting, transparency and color, it is not necessary to include a brilliance description. Differences of hardness and refractive index are also factors and do not allow all material to achieve the same level of brilliance.

The above terminology to describing color, clarity and cut provides a practical approach to characterizing material that is not seen under laboratory conditions. However, our reviewers are trained gemologists/appraisers and look at the pieces with well-practiced eyes.

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Descriptive data consider factors which are a bit different than those considered for gemstones. The following table lists those factors and explains what we look for:

meter Size For loose round pearls one dimension is given. For off round and baroque shapes, two dimensions are given. For graduated strands, the smallest and largest measurements i.e., 4 to 8 mm. For uniform strands, there is usually .5 mm variation between the largest and smallest pearls, indicated as 6 to 6.5 mm.
Pearl Color This refers to the basic predominant color you see.
Overtone This refers to (a) color(s) which appear(s) to overlay the basic color (as above).
Luster The degree of detail of reflections which can be seen on the surface of the pearl. A strong luster will show sharp edges of whatever is being reflected, such as a light bulb, a face, or a pencil. Lower luster will show fuzzy edges of the item and poor luster may not have a surface reflection at all.
Nacre This refers to the thickness of the layers which the oyster has deposited on the mother-of-pearl seed material. The oyster considers the seed, or even sand, an irritant and deposits material over it. The thickness may be seen in the drill holes of pearls, but if the pearl is cemented to a post or a strand is knotted very tightly then it is hard to judge. In these cases, we use the luster as a guide to nacre thickness; if the luster is high we feel the nacre is thick, and if the luster is low then the nacre must be very thin.
Match Pearls should be either well matched for color or properly blended. If shape or luster is badly matched it will be mentioned in "Notes."
Blemishes Blemishes refer to spots, wrinkles, indentations, bumps and/or orange peel surface. Description explains how noticeable they are to the naked eye. Unusual combinations of blemishes will also be reported in "Notes."
Full Pearl We report if pearls have been shaved or ground down to ½ or 3/4 pearls.
Shape Shapes will be described as round, off round, pear, barrel, button semi-baroque and baroque. Some baroque shapes will be defined as a figure (Donald Duck, a bird, etc.).
Processed Most pearls go through a processing procedure in which they are irradiated, bleached and/or sometimes dyed. Detection may prove difficult outside of lab conditions.

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Abbreviations Used

Abbreviation Meaning   Abbreviation Meaning
Bag Baguette   OP Opaque
Bar Baroque   OS Over scale
BO Black Onyx   Ov Oval
Br Brown   Pr Pair
Cal, CAL Calibre   Prl Pearl
CC Rect, CCRE Cut Corner Rectangle   RBC Round Brilliant Cut
CC Square, CCSQ Cut Corner Square   RC Rose cut
CC Tri, CCTR Cut Corner Triangle   Rd Round
Ctw Total Carat Weight   Rect Rectangle
Cush Cushion   Ru Ruby
CYAN Equal Mix of Green and Blue   Sa Sapphire
Dia Diamond   SC Single Cut
Ex Excellent   Sim Simulated
Fac Faceted   Sl Slight(ly)
FC Full Cut   Str Straight
Gd Good   Syn Synthetic
Gr Gray   Tap Tapered
Imit Imitation   Th Thick
MAG Magenta   TL Translucent
Med Medium   TP Transparent
Mod Moderate   Tri Triangle
Mod Br Modified Brilliant   VG Very Good
MOP Mother of Pearl   WG White Gold
Nat Natural   Wh White
Oct Octagon   Yel, YLW Yellow
OE Old European   YG Yellow Gold
OM Old Mine      

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