Pearl

Introduction

One of earliest gems materials used for adornment eg: 1400 yrs ago, Byzantine.

Form in a certain shell as the result of damage or intrusion of foreign body. If done by human intervension = cultured pearl. If a piece of shell (or material known as a bead) is inserted into a shell = beaded cultured pearl. If piece of soft organic tissue from animal is inserted = non-beaded cultured pearl. Process of introducing the irritant to the mollusk is called nucleating.

Until early 20th century only natural pearls were available on the market. Then Kokichi Mikimoto introduced cultured pearls grown in Japan, to the international market. Mother-of-pearl is inserted into a live oyster, then left to grow. Previously took 2 years but now 3-6 months. Output of Chinese freshwater pearls is measured in tons.

Today most are cultured using a variety of molluscs, across the world, in marine & freshwater reservoirs. Determination of mollusc used is important & may affect desirability. Specific difference between grown in freshwater (mussels, more abundant) or saltwater (oysters, eg: Akoya, South Sea or Tahitian cult. pearls which fetch higher prices).

Natural pearls are now rare and expensive. Special interest in them in the Middle East and India. Complex testing (X-ray and CT scans) are needed to confirm a natural origin. Can spot imitations of glass or plastic with a loupe (but hard to tell natural from cultured). Many imitations - glass, plastic, shells coated to imitate pearl nacre. Older coating was powdered fish scales on glass. To tell if an imitation - rub gently on top teeth, real pearl will feel rough while a simulant with feel smooth (not for natural vs cult, though).

Deteriorate overtime. Heat can cause cracking. Don't use chemicals or acids. Easily damaged. Mohs 2.5 to 4.5.

Continuity: Collecting top quality pearl strands may take many years. Dealers continuously source pearls matching in the 5 virtures and in the end the set will have a premium.

Lore: respresents modesty, chastity, purity; sumbolises beauty, love, success, happiness; wedding gift in many countries.

Pearl Orient

Optical phenomenon caused by reflected light on sub-surface of the nacreous material = iridescence. Called 'orient' in the past, in Europe.

Ponds/rivers were used for production of freshwater pearls (Scotland/Russia/Saxony) and most of these had poor lustre. Better lustre came from Arabian Gulf (Bahrain) and Far East.

Is also why people still ask 'does the pearl have a 'good orient'?

Value

Five virtures (+1 added):

• lustre
• size
• shape
• colour
• surface appearance
• added - determination of host mollusc

Lustre

Quality and quantity of light relecting from nacreous surface.

Excellent lustre - sharp, bright & distinct reflections.

Poor lustre - diminished & diffused reflection.

Shape

Rare to get a perfect round shape. Almost-rounds / near-rounds / off-rounds are almost identical to the untrained eye & are more abundant.

Irregular shapes called 'baroques'.

Inbetween these are collectively called 'semi-baroque' - pear or drop shapes, button & oval (with axis of symmetry). Are normally used as matching pairs for earrings.

Colour

Described as a combination of body colour (overall appearance), overtone (additional colour like green, pink, blue) & orient (coloured iridescent effects from subsurface).

Tahitian cult. pearls usually have darker hues / South Sea (Philipines) cult. pearls are golden / Fijian are pastel / Australia South Seas are white to silver-grey / Akoya are pinkish

Arab Roots of Gemolgy

Some elements from 'Arab roots of gemolgy: Ahmad ibn Yusuf Al Tifaschi's Best Thoughts on the Best of Stones' (c.1240) trans. Samar Najm Abul Huda. The Scarecrow Press, London, 1998.

Many names for pearls:

• Djumahana and Shazar (plural) refer to drilled pearls, as does Lou'lou' (small pearl)
• Durr (large pearl), Habb (small) and Khara'ed are undrilled (plural)
• al Thuma is white pearl (sing.)
• Khafrada (sing.)
• Djawhar a general term that applies to large and small
• Mardjan are seed pearls
• F arra is the best, round & spherical pearl without blemishes. Refered to by dealers a the 'running'. Farra is pure in colour with good water (the sheen) and of translucent core (the orient). Pearls that possess these qualities are called, by jewellers, ratb.

Pearls are found in many place but the best and most precious are in Sarandeeb, Kish, Oman, Bahrain and the island of Kharq (in Persian lands). Pearls found in deep water and locations free from heat show better purity, sheen and colour, as the heat of the sun gives a yellowish tint.

Perfect pearl is valuable on accounof iether its large size and heavey weight or qualites of strong white colour, good clarity and orient, even distribution and strength of colour, completely spherical shape. Valuable pearl is round, spherical, pure, translucent, of large size and heavy weight, with a small drill hole, of good white colour and free of dirt.

Pearls are formed of thin layers, and those that are not are man-made. Defects include - scalling, irrelgular shape, yellow or off-white colour, dull lustre, large drill hole, small size/weight.

Mixed in collyrium preparations as good for the eyes; good for heat palpiations, protect against fear and anguish; reduce blood clots in the heart; stop hemorrhage, give good polish to the teeth; dissolve pearls until they become like agitated water and spread over white leprosy spots or sniff this preparation to be cured of migrane due to (?) of the optic nerve.

In Baghdad the regular necklace is made of 36 pearls, the lightest weighing 4 carats. Prices can be bargained accounding to demand but inherent defects cannot be overlooked. The benefit of pearls derives from their beauty and appearance, not from another property as with other stones. They are wanted for adornment.

Things that can harm include grease, acid, esp. lemon juice, proximity to fire, contact with rough substances. When polishing must decide if the change is present in it own constitution or occured after usage. Examine it under sunlight. If you see the change is all over, inside and out, and it has not sheen then don't bother treating it as it cannot be polished. If you detect some light then dirt is superficial. If pearls are small then soak in the milk of a fig tree and change every three days until the pearl is clean. Another suggestion, of many, include powdered camphor or chalk placed in a rag with the pearl, the rag is palced in a jar of grease of mahlab seeds or of mercury, over a low coal fire for the time needed to count to 500, the process can be repeated.

American pearls

'Rock & Gem' (vol. 56, no. 6, pp.26-31, July 2026)

Freshwater river pearl from mussels (Unionidae) in the Mississippi River. Tennessee's state gem. Due to over harvesting, pollution, development many freshwater mussels now extinct or endangered.

Have names based on their shapes - wings, feathers, dogtooth, turtleback, snales, rosebud; Mostly white but also cream, pink, lavender, gold/bronze, sometimes blue.

c. 800 to 1650AD Mississippie area home to native culture who used Unionidae. crushed shell for pottery temper / food / shells for tools / jewellery from shell material or pearls.

Craig Mound, Spiro Mounds, Oklahoma, 1935 reported to contain thousands of freshwater pearls but artefacts were sold and distributed to private collections.

Hundreads of thousands beads (pearl and shell) found at Hopewell, Chillicothe, Ohio - documented by archaeologists as adjacent to burials of important individuals.

1857 pearl rush in New Jersey. eg: Quackenbush & Howell found a 23.35 15mm natural pink pearl at Notch Brook. Sold it to Tiffany & Co for $1500. They sold it to Empress Eugenie for 12,500 French francs. This set of a rush and pearls found as far as Texas. Often combined with gems such as Montana sapphire.

Unionidae aslo used to make buttons. By 1905 USA source of 35% of world's pearl buttons. Muscatine, Iowa was 'Pearl button capital of the world'. 1950+ had competition from other nations and development of plastic buttons and the industry waned.

WWII halted the pearl culturing trade but when it resumed Unionidae mussel became desired for oyster nucleation. Demand increased and at one point 10,000s musselers worked on Mississippi. American Pearl Company opened in 1961 (John Latendresse and wife Chieko Nakamoto) - if Japanese can culture pearls why can't we. Tried to culture Unionidae mussels but initially unsuccessful - have to learn the cycle of the mollusk. Took 14 years to start culturing Unionidae. First pearl cutting farm in USA was established in 1970s, on manmade lake near Lexington, Tennessee. Latendresse cultured dfferent shapes. Only one freshwater pearl farm still operates inTennessee - Kentucky Lake, Camden - founded by Latendresse but no longer owned by the family.