Let's answer some of your questions.

Q: Now-a-days everyone is selling those fresh water pearls. They’re really beautiful, and much cheaper than those Japanese Cultured pearls. I’d like to know more about them and how they compare. Why are the Japanese pearls so expensive, and are they that much better? Z.A.

A: To answer your question, I feel I should give you a short course in, “Pearls 101”.

JAPANESE AKOYA PEARLS:

Most Japanese cultured pearls are perfectly round (or almost so) because they are formed around a round bead. Approximately 100 years ago, Mr. Mikimoto (in Japan) developed a way to culture pearls in the Japanese Akoya oyster. His process involves the surgical implantation of a few round, manufactured beads into the body of the Akoya oyster. The bead is made of shell from the Mississippi River Pearl Shell Mollusk. After implantation, the oysters are placed in cages, attached to floating rafts, and placed back into the sea. The oysters remain under water, in their “farms”, for a number of years as they secrete layers of nacre (pearl material) over the bead. Perfectly round pearls are very rare in nature, and considered by many as unnatural.

Mr. Mikimoto was quite a showman, and like DeBeers did with diamonds, he created myths about his “perfect” round pearls. He created a demand for his pearls and made them a standard in the industry. Things he didn’t talk about are: 1) His pearls are primarily a manufactured bead covered with a few layers of nacre (pearl material); 2) Layers of nacre can peel off the center bead; 3) Although the pearls sold in his stores are “perfect”, many of the Japanese cultured pearls are imperfect (I’ve seen a lot of necklaces made from these junk pearls. Buyers are told the pearls are “Akoyas”, they pay high prices, and they get ripped off with these bad pearls).

Approximately 10 years ago a virus invaded the Japanese Akoya pearl farms, killing off many of the oysters. Because of this, the pearl farmers were forced to change their farming methods, and now the Akoya oysters must be harvested earlier than the optimum time necessary for premium pearls.

CHINESE CULTURED FRESHWATER PEARLS:

Historically, numerous freshwater mollusks, all around the world, have been producing fine pearls. Not long after Mr. Mikimoto developed his Akoya culturing process, a more natural process was developed for producing cultured pearls in freshwater mollusks. The process involves sacrificing a mollusk, then removing its’ mantle (a thin tissue), and cutting the mantle into numerous, tiny, fleshy squares. The living mollusks are seeded by technicians who cut numerous slits in their mantles and then insert tiny pieces of sacrificed mantle into the slits. The seeded mollusks are then placed in cages that are hung in freshwater ponds, and they remain there until they are harvested.

The pearls are produced when the mollusks’ bodies reject the inserted foreign tissue “seed”, and cover the “seed” with layers of secreted nacre. Next the “seed’ dissolves and is replaced with nacre. The freshwater pearl continues to grow, layer by layer, and, unlike the Japanese Akoya pearl, it is composed entirely of pearl. Also, unlike the Akoya, the freshwater mollusk can produce 20 to 40 pearls at a time. Because the freshwater pearls do not form around a round form, they tend to form in numerous semi round shapes; i.e. potato, rice, button, kishi, etc. Round, and nearly round, freshwater pearls do form, they are rare, and they are priced higher than round Akoya pearls. Freshwater pearl farmers do produce some special shaped pearls by inserting shaped solid seeds. Examples are: hearts; stars, squares, crosses, etc. The Chinese are currently experimenting seeding the freshwater mollusks with the round shell beads used in the Akoyas. Some freshwater pearl technicians are taking non-round pearls, grinding them perfectly round, and placing them back into another mollusk for more layers of nacre, thus producing perfectly round pearls.

Now to the question, which is a better pearl? As far as I, and numerous pearl experts, are concerned, a fine freshwater pearl is the better pearl of the two. Reasons include: 1) they have the same composition, technical qualities, surfaces, lusters, etc; 2) the freshwater pearl is all solid pearl, whereas, the Akoya pearl is a few layers of pearl over a manufactured bead; 3) the layers of the Akoya pearl can separate from the center bead and can peel apart.

Historically speaking, freshwater pearls from rivers, streams, ponds, and lakes, have been harvested, treasured, and used, throughout Europe, Asia, and the Americas, for thousands of years. Where as, natural ocean pearls are only found in a few locations in the world. In the past the USA was an important supplier of natural freshwater pearls, and currently has numerous freshwater pearl farms, in the south and west.

For more information, I recommend you check out this site: www.pbs.org/wgbh/nova/pearl/

 

 


And now back to our toughness chart


GEM NAME: COLORS: HARDNESS: TOUGHNESS: NOTES
RHODOCHROSITE  ROSE/RED-YELLOWISH    4 FAIR STRIPED.  STALAGTITE FORMED.
RHODONITE DK/RD-FLESH/RD 5.5-6.5 GOOD BLACK DENDRITIC INCLUSIONS.  CAN BE PINK/GREY.
   FOWLERITE BROWNISH OR YELLOWISH TINT            
RUBY IN ZOISITE       SEE ZOISITE
SCAPOLITE YW, PK,VL, CL 5.5-6 POOR VITRIOUS LUSTER.  CATS’EYES ARE KNOWN.
SERPENTINE GN, YELLOWISH, BN  2.5-5.5  FAIR SENSITIVE TO ACID.  INPROPERLY CALLED A “JADE”.
SODALITE WT, BL, GY 5.5-6 GOOD CONFUSED WITH LAPIZ LAZULI.
SPHENE YW, BN,GN, REDDISH   5-5.5 FAIR   AKA: TITANITE.  HEAT CHANGES COLOR TO RED OR ORANGE.
SPINEL ALL 8 GOOD MAY BE BRITTLE.  LIGHT COLORS MAY FADE IN INTENSE HEAT.  MANY FAMOUS & HISTORIC RUBIES ARE ACTUALLY SPINELS.
SPODUMENE GROUP  GNS, VTS   6.5-7 POOR

AVOID THERMAL SHOCK.  FUSES EASILLY UNDER TORCH. COLOR STRONGEST ON AXIS.

   HIDDENITE YW/GN, GN/YW, EMERALD GN     IF IRRADIATED, GREEN FADES IN MINUTES TO HOURS.
   KUNZITE PINK/VIOLET, LIGHT VIOLET     MOST STONES ARE LIGHTLY COLORED AND COMMONLY FADE.BROWNISH AND GREEN/VIOLET COLORS CAN BE IMPROVED BY HEATING  TO 300 deg.F.
SUGILITE VIOLET 5.5-6.5 GOOD TRANSLUCENT TO OPAQUE.
TANZANITE       SEE ZOISITE
TIGER’S EYE GD/YW, GD/BN   6.5-7 GOOD HAS A WAVY  EYE EFFECT.  AVOID THERMAL SHOCK. RED IS DYED.
   HAWK’S EYE BLUE/GRAY, BLUE/GREEN     SAME EFFECT AS TIGER’S EYE.  SENSITIVE TO ACID.
   TIGER IRON GD/YW, GD/BN, REDS     AKA: TIGER’S EYE MATRIX.  AGGREGATE LAYERS W/ IRON OXIDE              .
TOPAZ ALL & CL 8 POOR YELLOW WITH  RED TINT.IS MOST COMMON, PINK TO REDDISH-ORANGE YELLOWISH-BROWN GEMS.  THERE IS NATURAL BLUE TOPAZ, BUT MOST BLUE STONES ARE COLORLESS TOPAZ THAT HAS BEEN IRRADIATED & THEN HEATED.   AVOID THERMAL SHOCK. LIGHT BLOWS CAN CAUSE  CLEAVAGE.  HEAT MAY CAUSE COLOR CHANGE OR FADING. CITRINE & SMOKEY QUARTZ ARE WRONGLY CALLED TOPAZES.    
TOURMALINE GROUP     ALL 7-7.5 FAIR MOST CRYSTALS HAVE MORE THAN ONE COLOR.  “WATERMELON” HAS A RED INTERIOR & A GREEN EXTERIOR.  DEEP PINK & GREEN ARE THE MOST DESIREABLE.  TOURMALINE CATS’-EYES OCCUR.  AVOID THERMAL SHOCK. COLOR CHANGES PRODUCED BY IRRADIATION ARE NOT PERMANENT. HEAT CAN CAUSE SOME GREENS TO CHANGE COLOR.LATELY, VARIETY NAMES ARE BEING DROPPED AND STONES ARE CALLED “TOURMALINE”, PRECEEDED BY THE COLOR NAME. 
TURQUOISE     SKY-BL, BL/GN, 5-6 POOR-GOOD ALSO, APPLE-GREEN & BROWNS. USUALLY INCLUDES VEINING &/OR MATRIX. STONE SCRATCHES EASILLY.  THE COLOR CAN BE RUINED BY: HEAT, LIGHT, PERSPIRATION, OILS, COSMETICS, & HOUSEHOLD DETERGENTS, AND BY THE LOSS OF THE STONE’S WATER CONTENT. MUCH TURQUOISE IS COLORED AND STABLIZED WITH  RESINS.  SOME STONES HAVE THEIR COLOR STABLEIZED W/ELECTRICITY “WHITE BUFFALO” IS MAGNESITE & NOT TURQUOISE. 
UNAKITE MIXED GN, PK, WT.   GOOD       OPAQUE GRANITIC ROCK W/FELDSPAR, QUARTZ, EPIDOTE, ETC.       .
VARACITE YW-GN, BLUISH 4-5 FAIR    FREQUENTLY INTERMIXED WITH A BROWN MATRIX.
VERDITE LT-DK GREEN 3 FAIR OFTEN SPOTTY.  A SERPENTINE ROCK. TRANSLUCENT-OPAQUE.
ZIRCON GROUP ALL & CL 6.5-7.5 FAIR-POOR KNOWN SINCE ANCIENT TIMES, BUT UNDER NUMEROUS NAMES.  HIGH REFRACTIVE INDEX AND STRONG DISPERSION PRODUCES GREAT BRILLIANCE AND INTENSIVE FIRE.  BRITTLE AND SENSITIVE TO KNOCKS & PRESSURE.  EASY EDGE DAMAGE.  HEAT CAN CAUSE COLOR CHANGES. SOME COLORS PRODUCED BY HEATING CAN REVERT TO THE ORIGINAL COLOR WHEN EXPOSED TO LIGHT.  CAT’S-EYE  
   HYACINTH YW, YW/RD-RD/BN      
   JARGON STRAW/YW-ALMOST COLORLESS      
   STARLIGHT BLUE     CREATED BY HEATING & CAN FADE W/EXPOSED TO UV &/OR SUNLIGHT.  . 
ZOISITE GROUP   7-6 POOR  
   TANZANITE TP.  SAPPHIRE BL, AMETHYST, VL     IN GOOD QUALITY STONES THERE IS A COLOR CHANGE FROM BLUES UNDER DAYLIGHT TO VIOLETS UNDER ARTIFICIAL LIGHT.  BY HEATING TO 400-500 deg.C YELLOWISH AND BROWN TINTS VANISH AND THE BLUE DEEPENS.  THE GEMS CAN BE BRITTLE, CLEAVES, AND ABRADES EASILY.AVOID HEAT AND THERMAL SHOCK.  FUSES UNDER TORCH.  TANZANITE CAT’S EYES ARE FOUND.
   THULITE DENSE, OPAQUE PINK   FAIR-GOOD “LAPIZ NEVADA” IS A THULITE-DIOPSIDE SKARN ROCK .
   ANYOLITE GREEN W/BLACK & RUBY INCLUSIONS     AKA: RUBY IN ZOISITE.  BLACK INCLUSIONS ARE HORNBLEND.
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