Big Ideas

Peter Schjeldahl writes about the Venice Biennale—the most venerable of international art shows—directed by the American curator, critic, and teacher Robert Storr + other viewpoints @ http://www.newyorker.com/arts/critics/artworld/2007/06/25/070625craw_artworld_schjeldahl

Rough Diamonds’ Fatigue

Chaim Even-Zohar writes about worldwide rough diamond (2005) production (s) + the London connection + the South Africa connection + Dubai / Swiss connection (s) + Australia / London / Belgium connection (s) + the rough diamonds that never made it to London + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=25508

Black Opaque Gem Materials

Hematite
RI: 2.94-3.22; SG: 4.95-5.16; Luster: Metallic; Comments: Sometimes magnetic

Uraninite
SG: 5.2-10.0; Luster: Submetallic, resinous; Comments: Radioactive

Diamond
RI: 2.417; SG: 3.52; Luster: Adamantine

Irradiated Black Diamond
RI: 2.417; SG: 3.52; Luster: Adamantine; Comments: Sometimes radioactive

Cassiterite
RI: 2.006-2.097; SG: 6.99; Luster: Adamantine to vitreous

Hausmannite
RI: >1.81; SG: 4.84; Luster: Adamantine

Psilomelane (Mn oxides)
RI: > 1.81; SG: 4.35; Luster: Metallic to submetallic

Spinel Group
Magnetite
RI: 2.42; SG: 5.20; Luster: Metallic; Comments: Magnetic
Hercynite
RI: >1.81; 1.835; SG: 4.40; Luster: Subadamantine; Comments: Sometimes magnetic
Spinel
RI: 1.77; SG: 3.83; Luster: Vitreous
Intermediate spinel-hercynite
RI: 1.765; SG: 3.93; Luster: Subadamantine to vitreous

Garnet Group
Andradite garnet (melanite)
RI: 1.885; SG: 3.84; Luster: Subadamantine to vitreous
Pyrope
RI: 1.740; SG: about 3.72; Luster: Vitreous

Corundum (star sapphire)
RI: 1.760-1.78; SG: 3.989-4.0; Luster: Subadamantine to vitreous

Pyroxene Group
Augite
RI: 1.702-1.728; SG: 3.20-3.35; Luster: High vitreous
Diopside (star)
RI: 1.675-1.701; SG: 3.33; Luster: Vitreous
Jadite jade
RI: 1.65-1.67; SG: 3.20-3.34; Luster: Vitreous
Tourmaline
RI: 1.622-1.655; SG: 3.15-3.20; Luster: Vitreous

Amphibole Group
Ferrohornblende
RI: 1.60-1.70; SG: 3.36; Luster: Vitreous
Nephrite jade
RI: 1.600-1.641; SG: 2.90-3.02; Luster: Vitreous
Cummingtonite-grunerite
RI: 1.54-1.65

Jet
RI: 1.59-1.66; SG: 1.20-1.30; Luster: Resinous

Ekanite
RI: 1.593-1.595; SG: about 3.30; Luster: Vitreous: Comments: Radioactive

Labradorite Feldspar
RI: 1.560-1.568; SG: 2.69; Luster: Vitreous; Comments: Colored by inclusions

Dyed Chalcedony (black onyx)
RI: 1.530-1.539; SG: 2.57-2.64; Luster: Vitreous

Chalcedony with Psilomelane
RI: 1.535-1.539; SG: 3.0-3.1; Luster: Metallic to submetallic; Comments: Banded

Coated Quartz
RI: 1.54; Luster: Vitreous to dull

Dolomite
RI: 1.51-1.67; SG: 2.8-2.9; Luster: Vitreous

Black Coral
RI: 1.56; SG: 1.34; Luster: Resinous

Obsidian
RI: 1.48-1.52; SG: 2.30-2.50; Luster: Vitreous

Opal (black opaque)
RI: 1.44; SG: 2.02; Luster: Vitreous

Rocks (aggregates)
Dolomite/quartzite rock
RI: 1.66 spot; SG: 2.74; Luster: Vitreous

Simulants
Cubic zirconia
RI: 2.14; SG: 6.14-6.16; Luster: Adamantine
Silicon
RI: >1.81; SG: 2.34; Luster: Metallic: Comments Gray
Hematine
RI: >1.81; SG: 4.00-7.00; Luster: Metallic; Comments: Magnetic
YIG (ytrrium iron garnet)
SG: about 6; Luster: Vitreous to submetallic; Comments: Magnetic
Barrium sulfate/polymer
RI: mid-1.50s; SG: 2.26-2.33
Plastics
RI: 1.5-1.6; SG: 1.05-1.55; Luster: Vitreous to resinous
Glass
RI: 1.35-1.70; SG: 2.51-3.21; Luster: Submetallic to vitreous

Smaragdite

(variety of Actinolite)
Crystal system: Monoclinic; massive.
Color: Translucent to opaque: yellowish green to bluish green.
Hardness: 6.5
Cleavage: -
Specific gravity: 3.25
Refractive index: 1.608 – 1.630; Biaxial negative; 0.022; 1.62 mean.
Luster: Vitreous
Dispersion: -
Dichroism: -
Occurrence: Austria, France, Italy, USA, Philippines

Notes
Chloromelanite may be a variety; part of the amphibole group of minerals; difficult to distinguish from jadeite to which it is closely related; carvings.

Buying Gold? Getting Cheated!

Ronojoy Banerjee writes about the survey (I wasn't surprised) conducted by The Bureau of Indian Standards on the purity of gold in India @ http://www.outlookmoney.com/scripts/ptifile.asp?pti_news_id=738

More Than You Know

Good Books: (via Emergic) Michael Mauboussin is chief investment strategist at Legg Mason Capital. His book More Than You Know is a collection of his essays written over the past few years.

Here is what Publisher’s Weekly has to say (via Amazon.com):
Mauboussin is not your average Wall Street equity analyst, writing investment recommendations whose topical interest wanes a few days after the report is issued. His strategy reports begin with scientific findings from diverse fields, then show why an investor should care. This book is a collection of 30 short reports, revised and updated, covering animal behavior ("Guppy Love: The Role of Imitation in Markets"), psychology ("Why Zebras Don't Get Ulcers"), philosophy of science ("The Janitor's Dream: Why Listening to Individuals Can be Hazardous to Your Wealth") and other fields. Each essay describes a fascinating scientific finding, then develops and applies it to personal investing. "Survival of the Fittest," for example, begins by discussing how Tiger Woods improved his golf swing, introduces the concept of fitness landscapes from evolutionary biology, then explains why investors in commodity-producing companies should like strong centralized management, while technology-stock buyers should prefer flexible organizations with lots of disruptive new ideas. The book is breezy and well written, but not dumbed down, and provides extensive references. It can be read for entertainment as popular science or to broaden your investment thinking.

You can find some of Mauboussin’s recent essays here.

This is a fascinating book + gem and jewelry professionals + entrepreneurs must read the book for insights because you will meet the same type of characters in the (any) industry.

Modern Love

Peter Schjeldahl writes about the art and style of Sara & Gerald Murphy@ http://www.newyorker.com/arts/critics/artworld/2007/08/06/070806craw_artworld_schjeldahl

Canadian Diamond Anti-Money Laundering Rules In-The-Making

Chaim Even-Zohar writes about Canadian government's overstated concerns posed by the diamond industry + BHP Billiton's suggestions on the methodology of reporting transactions + client identification difficulties + AML/CFT compliance agenda (s) + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=25527