mcc diamond morphology...mcc octahedral surface features serrate laminae are sharp points and shield...

MCC

www.mccgeoscience.com

Diamond MorphologyDiamond Morphology

Tom E. McCandlessTom E. McCandless

MCC Geoscience Inc.MCC Geoscience Inc.North Vancouver, BC, CanadaNorth Vancouver, BC, Canada

[email protected]@gmail.com

www.mccgeoscience.comwww.mccgeoscience.com

SRK SRK –– 1 November 20131 November 2013

MCC


MineMine grade, grade, cts/tcts/t

HelamHelam 1515

Argyle Argyle 66

DiavikDiavik 33

JwanengJwaneng 1.41.4

Venetia Venetia 1.21.2

EkatiEkati 1.01.0

FinschFinsch 0.80.8

OrapaOrapa 0.70.7

Premier Premier 0.40.4

Williamson Williamson 0.20.2

LetsengLetseng 0.020.02

(five carats = one g/tonne)(five carats = one g/tonne)

‘‘‘‘Lesotho PromiseLesotho PromiseLesotho PromiseLesotho Promise’’’’, 603 carats; , 603 carats; , 603 carats; , 603 carats; $12,000,000 uncut; $12,000,000 uncut; $12,000,000 uncut; $12,000,000 uncut;

$20,000,000 after cutting.$20,000,000 after cutting.$20,000,000 after cutting.$20,000,000 after cutting.(mine (mine (mine (mine ‘‘‘‘gradegradegradegrade’’’’ = 4 ppb)= 4 ppb)= 4 ppb)= 4 ppb)


$20,000,000 after cutting.$20,000,000 after cutting.$20,000,000 after cutting.$20,000,000 after cutting.(mine (mine (mine (mine ‘‘‘‘gradegradegradegrade’’’’ = 4 ppb)= 4 ppb)= 4 ppb)= 4 ppb)

Large diamonds are very rareLarge diamonds are very rareLarge diamonds are very rareLarge diamonds are very rareLarge diamonds are very rareLarge diamonds are very rareLarge diamonds are very rareLarge diamonds are very rareMCC

MCC


There are two primary forms of diamond- the cube and the octahedron.

Diamond CrystallographyDiamond CrystallographyDiamond CrystallographyDiamond CrystallographyDiamond CrystallographyDiamond CrystallographyDiamond CrystallographyDiamond Crystallography

a1

a2

a3

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O

C

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Cubes and octahedra are modified by resorption of the Cubes and octahedra are modified by resorption of the primary forms, and is often called a dodecahedron, primary forms, and is often called a dodecahedron,

dodecahedroiddodecahedroid, or rounded dodecahedron, or rounded dodecahedron

It is correctly called the It is correctly called the tetrahexahedroidtetrahexahedroid..

Diamond Resorption (Dissolution)Diamond Resorption (Dissolution)Diamond Resorption (Dissolution)Diamond Resorption (Dissolution)Diamond Resorption (Dissolution)Diamond Resorption (Dissolution)Diamond Resorption (Dissolution)Diamond Resorption (Dissolution)MCC

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Relation of Octahedron to THHRelation of Octahedron to THHRelation of Octahedron to THHRelation of Octahedron to THHRelation of Octahedron to THHRelation of Octahedron to THHRelation of Octahedron to THHRelation of Octahedron to THHMCC

Corners and edges dissolve like ice cubes in a gin and

tonic.

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www.mccgeoscience.com (picture from Wilson, 1982)(picture from Wilson, 1982)

Clear remnant (111) surfaces and textured resorption surfaces.

Partially resorbed diamond in Partially resorbed diamond in Partially resorbed diamond in Partially resorbed diamond in Partially resorbed diamond in Partially resorbed diamond in Partially resorbed diamond in Partially resorbed diamond in kimberlitekimberlitekimberlitekimberlitekimberlitekimberlitekimberlitekimberlite

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Superior Minerals Superior Minerals Superior Minerals Superior Minerals Superior Minerals Superior Minerals Superior Minerals Superior Minerals –––––––– 1981 1981 1981 1981 1981 1981 1981 1981 MCC

Derek N. Robinson, 1979, Surface Derek N. Robinson, 1979, Surface Textures and Other Features of Textures and Other Features of Diamonds, Ph.D., University of Diamonds, Ph.D., University of

Cape Town, Cape Town,

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171 Images scattered over 72 pages171 Images scattered over 72 pages171 Images scattered over 72 pages171 Images scattered over 72 pages171 Images scattered over 72 pages171 Images scattered over 72 pages171 Images scattered over 72 pages171 Images scattered over 72 pagesMCC

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Cubic surfaces are often more susceptible to resorption than octahedral surfaces.

Cubic Surface FeaturesCubic Surface FeaturesCubic Surface FeaturesCubic Surface FeaturesCubic Surface FeaturesCubic Surface FeaturesCubic Surface FeaturesCubic Surface FeaturesMCC

Tetragonal pits (positveand negative), cresentic

steps, pointed plates

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It grows by stacking carbon layers to the (111) faces, expressed by parallel steps or lines along the crystal edges.

Octahedral Growth StructureOctahedral Growth StructureOctahedral Growth StructureOctahedral Growth StructureOctahedral Growth StructureOctahedral Growth StructureOctahedral Growth StructureOctahedral Growth Structure

The octahedron is the most common primary form, and exhibits a distinctive growth structure.

The growth layers are called triangular plates. The plate heights are exaggerated here.

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Octahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface Features

serrate laminae are sharp points and shield laminae

are blunt points

trigonal pits, usually negative orientation, can be flat- or point-bottomed

ribbing is the rounding of growth

layers at (111) edges, to form (110) surfaces

These are features of early or restricted degrees of resorption.

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Octahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesOctahedral Surface FeaturesThe octahedral surface features

transition into tetrahexahedroidalsurface features with longer

and/or more severe resorption.

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Tetrahexahedroidal Surface FeaturesTetrahexahedroidal Surface FeaturesTetrahexahedroidal Surface FeaturesTetrahexahedroidal Surface FeaturesTetrahexahedroidal Surface FeaturesTetrahexahedroidal Surface FeaturesTetrahexahedroidal Surface FeaturesTetrahexahedroidal Surface Features

Hillocks (elongate, pyramidal, fine, zigzag, transverse,

imbricate, shagreen, semi-cylindrical, rhombic), terraces, zig-zag, shagreen, low-relief,

corrosion sculpture.

Hillocks are the resorbed edges of triangular plates.

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Advanced (Advanced (Advanced (Advanced (thhthhthhthh) Surfaces) Surfaces) Surfaces) Surfaces

Under extreme conditions, hillocks become completely subdued and a glassy surface results.

low relief surface

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Lamination lines are evidence of structural dislocation of the diamond crystal.

Unrestricted Surface Features (early)Unrestricted Surface Features (early)Unrestricted Surface Features (early)Unrestricted Surface Features (early)Unrestricted Surface Features (early)Unrestricted Surface Features (early)Unrestricted Surface Features (early)Unrestricted Surface Features (early)MCC

Lamination lines appear as ‘ruled shadows’ on THH.

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Forms late in the resorption process. Common on diamonds from deeper in the kimberlite and/or from dikes and sills.

Unrestricted Surface Features (late)Unrestricted Surface Features (late)Unrestricted Surface Features (late)Unrestricted Surface Features (late)Unrestricted Surface Features (late)Unrestricted Surface Features (late)Unrestricted Surface Features (late)Unrestricted Surface Features (late)MCC

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Octahedral Tetrahexahedroidal Cubic

trigonal pits hillocks tetragonal pits

shield laminae low relief surfaces pointed plates

serrate laminae crescentic steps

ribbing

knob-like asperities

deformation, corrosion sculpture

Diamond Surface FeaturesDiamond Surface FeaturesDiamond Surface FeaturesDiamond Surface FeaturesDiamond Surface FeaturesDiamond Surface FeaturesDiamond Surface FeaturesDiamond Surface Features

General rules: - octahedral features occur on flat surfaces

- thh features occur on convex surfaces- cubic surfaces are undulatory concave

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(Robinson, 1979)

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Diamond (g) exhibits uneven resorption, with hillocks on the right, and triangular plates still present on the left.

Diamond (h) also exhibits uneven resorption, with ribbing and serrate laminae on the upper part, and hillocks on the lower part.

Uneven ResorptionUneven ResorptionUneven ResorptionUneven ResorptionUneven ResorptionUneven ResorptionUneven ResorptionUneven Resorption

Uneven resorption is evidence of a xenolithic origin for diamond.

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OctahedralOctahedral Tetrahexahedroidal Tetrahexahedroidal CubicCubic

trigonaltrigonal pitspits hillockshillocks tetragonal pitstetragonal pits

shield laminae shield laminae low relief surfaceslow relief surfaces pointed platespointed plates

serrate laminaeserrate laminae crescenticcrescentic stepssteps

ribbing ribbing

knobknob--like asperitieslike asperities(Robinson, 1979, McCandless et al, 1994)(Robinson, 1979, McCandless et al, 1994)


ms

fx

sf

msf = macrocrystic surface features – most often observed on commercial-size diamonds

xsf = xenocrystic surface features – most often observed on diamonds partially or completely enclosed in parent

rocks during resorption

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1. Diamonds develop surface 1. Diamonds develop surface

textures during resorption textures during resorption

that are specific to crystal that are specific to crystal

orientation.orientation.

2. Unrestricted surface textures 2. Unrestricted surface textures

also develop on diamonds.also develop on diamonds.

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3. Microdiamonds exhibit the 3. Microdiamonds exhibit the

same crystal forms as same crystal forms as

commercialcommercial--size diamonds size diamonds

((macrodiamondsmacrodiamonds).).

4. Microdiamonds in kimberlite 4. Microdiamonds in kimberlite

are mostly octahedral shapes.are mostly octahedral shapes.

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5. Whole microdiamonds have 5. Whole microdiamonds have

morphologies and surface morphologies and surface

features consistent with features consistent with

derivation from xenoliths.derivation from xenoliths.

6. Microdiamonds are not 6. Microdiamonds are not

phenocrysts in kimberlite.phenocrysts in kimberlite.

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5. Microdiamonds 5. Microdiamonds in theoryin theory may may

be preserved in cooler carbon be preserved in cooler carbon

saturated regions of the saturated regions of the

ascending kimberlite.ascending kimberlite.

6. Microdiamond growth during 6. Microdiamond growth during

kimberlite ascent is unlikely to kimberlite ascent is unlikely to

contribute mass or numbers to contribute mass or numbers to

the micro population. (FC)the micro population. (FC)

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Classification by Surface FeaturesClassification by Surface FeaturesClassification by Surface FeaturesClassification by Surface FeaturesClassification by Surface FeaturesClassification by Surface FeaturesClassification by Surface FeaturesClassification by Surface Features

Octahedral (xsf)Octahedral (xsf)

((trigonaltrigonal pits, triangular pits, triangular

plates, serrate laminae, plates, serrate laminae,

shield laminae)shield laminae)

CubicCubic

(tetragonal pits, pointed (tetragonal pits, pointed

plates, plates, crescenticcrescentic steps)steps)

Thh (msf)Thh (msf)

(hillocks, low(hillocks, low--relief surfaces, relief surfaces,

corrosion sculpture)corrosion sculpture)

BreakageBreakage

((subconchoidalsubconchoidal breaks, breaks,

cleavages)cleavages)

octahedronoctahedronoctaocta--surface surface

fragmentfragment

cubiccubiccubiccubic--surface surface

fragmentfragment

thhthhthhthh--surface surface

fragmentfragment

fragmentfragment

Microdiamond Surface FeaturesMicrodiamond Surface Features

>50% crystal>50% crystal<50% crystal<50% crystal

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7. Bulk fusion isn7. Bulk fusion isn’’t.t.

8. Microdiamond populations 8. Microdiamond populations

include naturallyinclude naturally--occurring occurring

fragments, that are fragments, that are notnot from from

sample treatment.sample treatment.

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�� Commercial diamond contents are low in kimberliteCommercial diamond contents are low in kimberlite

�� To assess commercial diamond potential, 100To assess commercial diamond potential, 100’’s to s to 1,0001,000’’s of tonnes of kimberlite would have to be s of tonnes of kimberlite would have to be treated.treated.

�� Smaller diamonds occur in greater abundance in Smaller diamonds occur in greater abundance in kimberlite, so smaller amounts of kimberlite (10 to kimberlite, so smaller amounts of kimberlite (10 to 100100’’s of kilograms) could be treated, with commercial s of kilograms) could be treated, with commercial potential projected from the smaller stones. potential projected from the smaller stones.

The prediction assumes that: The prediction assumes that:

(1) microdiamonds will be present in a kimberlite;(1) microdiamonds will be present in a kimberlite;

(2) the microdiamonds are genetically related to (2) the microdiamonds are genetically related to the larger commercialthe larger commercial--sized diamonds; sized diamonds;

(3) microdiamonds are not broken during their (3) microdiamonds are not broken during their recovery from the kimberlite.recovery from the kimberlite.

Commercial Stones Commercial Stones Commercial Stones Commercial Stones Commercial Stones Commercial Stones Commercial Stones Commercial Stones vsvsvsvsvsvsvsvs MicrodiamondsMicrodiamondsMicrodiamondsMicrodiamondsMicrodiamondsMicrodiamondsMicrodiamondsMicrodiamondsMCC

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0.0

0.1

1.0

10.0

100.0

1000.0

10000.0

+0.1

00-0

.150

+0.1

50-0

.212

+0.2

12-0

.300

+0.3

00-0

.425

+0.4

25-0

.600

+0.6

00-0

.850

+0.8

50-1

.180

+1.1

80-1

.700

+1.7

00-2

.360

+2.3

60-3

.350

+3.3

50-4

.750

+4.7

50-6

.700

Sieve Class, mm

Dia

mo

nd

s p

er

to

nn

eKimberlite A- MDT 0.1517 t

Kimberlite A- DMS ~0.1cpt; 11 t

MCC SFD Plots SFD Plots SFD Plots SFD Plots SFD Plots SFD Plots SFD Plots SFD Plots –––––––– Kicks and DropKicks and DropKicks and DropKicks and DropKicks and DropKicks and DropKicks and DropKicks and Drop--------offsoffsoffsoffsoffsoffsoffsoffs

higher plot = more stonesflatter slope = bigger stones

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can produce logcan produce log--normal plots normal plots

with fragments present.with fragments present.

10. Mixed parent rock 10. Mixed parent rock

contributions (eclogite) may contributions (eclogite) may

explain nugget effects.explain nugget effects.

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MCC



will include contributions will include contributions

from different parent rocks.from different parent rocks.

12. All measurable aspects of 12. All measurable aspects of

microdiamonds should be microdiamonds should be

collected to interpret SFD collected to interpret SFD

plots more effectively.plots more effectively.

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MCC



Primary Features:

Developed on diamond during genesis (cube, cube-

octahedral, octahedral, twin, etc.)

Developed on diamond during mantle residence

(deformation, fracture, dissolution).

Developed during ascent in the igneous host rock.

Most are specific to each crystal surface type.

Some are unrestricted and form on all surfaces.

Secondary Features:

Developed after emplacement of the igneous host.

Natural and mechanical breakage, surface wear

(chipping, abrasion, scratching).

Radiation damage (spots, colouration).

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Diamond GenesisDiamond GenesisDiamond GenesisDiamond Genesis

Traditional

igneous processes

old events (>0.6 Ga)

static mantle

two parent rocks

harzburgitic most important

eclogite less important

lherzolite not important

Future

hydrothermal processes

young events (<0.6 Ga)

plate tectonics

multiple parent rocks

harzburgitic less important

eclogite most important

lherzolite more important

MCC


Bullet PointsBullet PointsBullet PointsBullet PointsDiamonds are xenocrysts in their igneous host.

They occur in three common forms.

Surface features are unique to each form.

Diamond wear and radiation damage is distinctive.

Fragments are a natural component of diamonds.

Microdiamonds are xenocrysts, physically similar to diamonds in xenoliths.

Microdiamonds may represent multiple parentrocks in the kimberlite

Diamond size frequency distribution plots tend to smooth out mixed parentages and histories

1

Valuation of DiamondsValuation of Diamonds

Tom E. McCandlessTom E. McCandless

MCC Geoscience, Inc.MCC Geoscience, Inc.North Vancouver, BC, CanadaNorth Vancouver, BC, [email protected]@gmail.com

www.mccgeoscience.comwww.mccgeoscience.com

3 April 20123 April 2012

MCC

MineMine grade, grade, cts/tcts/t

HelamHelam 1515

Argyle Argyle 66

DiavikDiavik 33

JwanengJwaneng 1.41.4

Venetia Venetia 1.21.2

EkatiEkati 1.01.0

FinschFinsch 0.80.8

OrapaOrapa 0.70.7

Premier Premier 0.40.4

Williamson Williamson 0.20.2

LetsengLetseng 0.020.02

(five carats = one g/tonne)(five carats = one g/tonne)


$20,000,000 after cutting.$20,000,000 after cutting.$20,000,000 after cutting.$20,000,000 after cutting.(mine grade = 4 ppb)(mine grade = 4 ppb)(mine grade = 4 ppb)(mine grade = 4 ppb)


$20,000,000 after cutting.$20,000,000 after cutting.$20,000,000 after cutting.$20,000,000 after cutting.(mine grade = 4 ppb)(mine grade = 4 ppb)(mine grade = 4 ppb)(mine grade = 4 ppb)

In Diamonds, Size Really MattersIn Diamonds, Size Really MattersIn Diamonds, Size Really MattersIn Diamonds, Size Really MattersIn Diamonds, Size Really MattersIn Diamonds, Size Really MattersIn Diamonds, Size Really MattersIn Diamonds, Size Really MattersMCC

2

The largest uncut stone, 616 carats, is riddled with inclusions.

and so does qualityand so does qualityand so does qualityand so does qualityand so does qualityand so does qualityand so does qualityand so does qualityMCC

The The The The The The The The ‘‘‘‘‘‘‘‘ScienceScienceScienceScienceScienceScienceScienceScience’’’’’’’’ of Diamond Valuationof Diamond Valuationof Diamond Valuationof Diamond Valuationof Diamond Valuationof Diamond Valuationof Diamond Valuationof Diamond ValuationMCC

Diamond valuation is not a science, but does operate on a combination of scientific principles, historic methodologies, and ‘field’ experience.

Diamond valuation is not a science, but Diamond valuation is not a science, but does operate on a combination of does operate on a combination of scientific principles, historic scientific principles, historic methodologies, and methodologies, and ‘‘fieldfield’’ experience. experience.

3

Diamond Valuation ScreensDiamond Valuation ScreensDiamond Valuation ScreensDiamond Valuation ScreensDiamond Valuation ScreensDiamond Valuation ScreensDiamond Valuation ScreensDiamond Valuation ScreensMCC

DTC screens are based on hole assignments created in Kimberley, South Africa in the late 1800’s. DTC screens are based on hole assignments created in DTC screens are based on hole assignments created in Kimberley, South Africa in the late 1800Kimberley, South Africa in the late 1800’’s. s.


Today, DTC screens are also used mostly for sizes less than 0.66 carats in mass. These are size divisions except for +11 DTC which is a mass division.

Today, DTC screens are also used mostly for sizes less Today, DTC screens are also used mostly for sizes less than 0.66 carats in mass. These are size divisions except than 0.66 carats in mass. These are size divisions except for +11 DTC which is a mass division.for +11 DTC which is a mass division.

4


Stones above 0.66 carats are further divided into grainer (gr.) and carat categories (ct.) according to weight ranges. Stones above 0.66 carats are further divided into grainer Stones above 0.66 carats are further divided into grainer (gr.) and carat categories (ct.) according to weight ranges. (gr.) and carat categories (ct.) according to weight ranges.


Within the market, DTC screens also differ slightly from Antwerp screens, adding to the confusion. Within the market, DTC screens also differ slightly from Within the market, DTC screens also differ slightly from Antwerp screens, adding to the confusion. Antwerp screens, adding to the confusion.

5

Diamond Value in a ParcelDiamond Value in a ParcelDiamond Value in a ParcelDiamond Value in a ParcelDiamond Value in a ParcelDiamond Value in a ParcelDiamond Value in a ParcelDiamond Value in a ParcelMCC

As a general rule, 80% of the value of a ROM parcel is contained in 20% of the total weight. As a general rule, 80% of the value of a ROM parcel As a general rule, 80% of the value of a ROM parcel is contained in 20% of the total weight. is contained in 20% of the total weight.

80% of the value80% of the value80% of the weight80% of the weight

DTCDTCDTCDTC----GrainerGrainerGrainerGrainer----Carat DinnerCarat DinnerCarat DinnerCarat DinnerDTCDTCDTCDTC----GrainerGrainerGrainerGrainer----Carat DinnerCarat DinnerCarat DinnerCarat Dinner

>2.8 ct>2.8 ct……

Carat

Carat

0.660.66--2.79 ct2.79 ct……

Grainer

Grainer

0.010.01--0.65 ct0.65 ct……DTC

DTC

MCC

6

Diamond Valuation ExampleDiamond Valuation ExampleDiamond Valuation ExampleDiamond Valuation ExampleDiamond Valuation ExampleDiamond Valuation ExampleDiamond Valuation ExampleDiamond Valuation ExampleMCC

Assume 80% of the value of a ROM parcel is contained in 20% of the total weight (don’t look at the -11 DTC’s in detail).

For ROM parcels exceeding ~1,000 carats, there is usually ten times the total number of stones.

For 1,000 carats, there are 10,000 stones total. Twenty-percent of which are +11 DTC (200 stones).

Two hundred stones for classifying into:

Assume 80% of the value of a ROM parcel is Assume 80% of the value of a ROM parcel is contained in 20% of the total weight (doncontained in 20% of the total weight (don’’t look at t look at the the --11 11 DTCDTC’’ss in detail).in detail).

For ROM parcels exceeding ~1,000 carats, there is For ROM parcels exceeding ~1,000 carats, there is usually ten times the total number of stones. usually ten times the total number of stones.

For 1,000 carats, there are 10,000 stones total. For 1,000 carats, there are 10,000 stones total. TwentyTwenty--percent of which are +11 DTC (200 stones).percent of which are +11 DTC (200 stones).

Two hundred stones for classifying into:Two hundred stones for classifying into:

Diamond Valuation Class MatrixDiamond Valuation Class MatrixDiamond Valuation Class MatrixDiamond Valuation Class MatrixDiamond Valuation Class MatrixDiamond Valuation Class MatrixDiamond Valuation Class MatrixDiamond Valuation Class MatrixMCC

Gem Z1 M1 CapeZ2 M2 Maacle TLBZ3 M3 Flat LBZ4 M4 LBBK

Near-Gem Z1 M1 LBZ2 M2 Maacle TLBZ3 M3 Flat LBZ4 M4 LBBK

Rejection Chip CapeClivage LB

TLBLBBK

Boart

GemGem Z1Z1 M1M1 CapeCapeZ2Z2 M2M2 MaacleMaacle TLBTLBZ3Z3 M3M3 FlatFlat LBLBZ4Z4 M4M4 LBBKLBBK

NearNear--GemGem Z1Z1 M1M1 LBLBZ2Z2 M2M2 MaacleMaacle TLBTLBZ3Z3 M3M3 FlatFlat LBLBZ4Z4 M4M4 LBBKLBBK

RejectionRejection ChipChip CapeCapeClivageClivage LBLB

TLBTLBLBBKLBBK

BoartBoart

Complex spreadsheets are required to calculate Complex spreadsheets are required to calculate an average carat price for a parcel.an average carat price for a parcel.

7

ConclusionsConclusionsConclusionsConclusionsConclusionsConclusionsConclusionsConclusionsMCC

Diamond valuators rely on a Diamond valuators rely on a Diamond valuators rely on a Diamond valuators rely on a

combination of combination of combination of combination of scientific principles (statistics),scientific principles (statistics),scientific principles (statistics),scientific principles (statistics),

historically unique features of historically unique features of historically unique features of historically unique features of

their discipline (DTCtheir discipline (DTCtheir discipline (DTCtheir discipline (DTC----GRGRGRGR----CT),CT),CT),CT),

and and and and ‘‘‘‘field experiencefield experiencefield experiencefield experience’’’’ (price book)(price book)(price book)(price book)

to determine the value of a single to determine the value of a single to determine the value of a single to determine the value of a single stone, or a parcel of stones. stone, or a parcel of stones. stone, or a parcel of stones. stone, or a parcel of stones.

Diamond valuators rely on a Diamond valuators rely on a Diamond valuators rely on a Diamond valuators rely on a

combination of combination of combination of combination of scientific principles (statistics),scientific principles (statistics),scientific principles (statistics),scientific principles (statistics),

historically unique features of historically unique features of historically unique features of historically unique features of

their discipline (DTCtheir discipline (DTCtheir discipline (DTCtheir discipline (DTC----GRGRGRGR----CT),CT),CT),CT),

and and and and ‘‘‘‘field experiencefield experiencefield experiencefield experience’’’’ (price book)(price book)(price book)(price book)

to determine the value of a single to determine the value of a single to determine the value of a single to determine the value of a single stone, or a parcel of stones. stone, or a parcel of stones. stone, or a parcel of stones. stone, or a parcel of stones.

ReferencesReferencesReferencesReferencesReferencesReferencesReferencesReferencesMCC

Chapman, J. 2004. Cutting & Polishing Chapman, J. 2004. Cutting & Polishing Chapman, J. 2004. Cutting & Polishing Chapman, J. 2004. Cutting & Polishing Costing. Rough Diamond Review, 6, 27Costing. Rough Diamond Review, 6, 27Costing. Rough Diamond Review, 6, 27Costing. Rough Diamond Review, 6, 27----30.30.30.30.

AnnonymousAnnonymousAnnonymousAnnonymous, 2003. A guide to rough diamond , 2003. A guide to rough diamond , 2003. A guide to rough diamond , 2003. A guide to rough diamond classification. Rough Diamond Review, 1, 9classification. Rough Diamond Review, 1, 9classification. Rough Diamond Review, 1, 9classification. Rough Diamond Review, 1, 9----12.12.12.12.

Boxer, G. 2004. Diamond Size Distributions. Boxer, G. 2004. Diamond Size Distributions. Boxer, G. 2004. Diamond Size Distributions. Boxer, G. 2004. Diamond Size Distributions. Rough Diamond Review, 7, 21Rough Diamond Review, 7, 21Rough Diamond Review, 7, 21Rough Diamond Review, 7, 21----24.24.24.24.

Chapman, J. 2004. Cutting & Polishing Chapman, J. 2004. Cutting & Polishing Chapman, J. 2004. Cutting & Polishing Chapman, J. 2004. Cutting & Polishing Costing. Rough Diamond Review, 6, 27Costing. Rough Diamond Review, 6, 27Costing. Rough Diamond Review, 6, 27Costing. Rough Diamond Review, 6, 27----30.30.30.30.

AnnonymousAnnonymousAnnonymousAnnonymous, 2003. A guide to rough diamond , 2003. A guide to rough diamond , 2003. A guide to rough diamond , 2003. A guide to rough diamond classification. Rough Diamond Review, 1, 9classification. Rough Diamond Review, 1, 9classification. Rough Diamond Review, 1, 9classification. Rough Diamond Review, 1, 9----12.12.12.12.

Boxer, G. 2004. Diamond Size Distributions. Boxer, G. 2004. Diamond Size Distributions. Boxer, G. 2004. Diamond Size Distributions. Boxer, G. 2004. Diamond Size Distributions. Rough Diamond Review, 7, 21Rough Diamond Review, 7, 21Rough Diamond Review, 7, 21Rough Diamond Review, 7, 21----24.24.24.24.

mcc diamond morphology...mcc octahedral surface features serrate laminae are sharp points and shield...

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