Pinctada maxima was recorded for the first time in northern Australian waters (Dakin, 1913). They are commonly called the silver-lipped or gold-lipped pearl oyster and produce the famous South Sea pearls (SSP)(O’Sullivan, 1992). It is the largest species in the genus Pinctada (Dakin, 1913; Hynd, 1955; Shirai, 1994; Xie, 1990) and it produces the largest and finest pearls (Kunz & Stevenson, 1908). Shell size may reach more than 30 centimetres and individuals may live for up to 40 years (Strack, 2006). Both Pinctada maxima (Jameson, 1901) and P. margaritifera (Linnaeus, 1758) are closely related species (He et al., 2005) and share the same position as the most primitive species within the genus Pinctada (Yu and Chu, 2006). P. maxima is distributed from the Indian Ocean to the Pacific and from the tropic of Cancer to the tropic of Capricorn (Wada & Tëmkin, 2008)(Fig. 1.1). They are found in depths of up to 90 metres although their optimal habitat is at about 35 metres (Strack, 2006).
Fig 1.1. Geographical distribution of Pinctada maxima (Wada & Tëmkin, 2008). The taxonomic position of Pinctada maxima is shown below:
Phyllum Mollusca >> Class Bivalvia >> Order Pterioida >> Family Pteriidae >> Genus Pinctada Röding, 1798 >> Species Pinctada maxima (Jameson, 1901)
1.2.2 Morphology and anatomy
The anatomy of Pinctada maxima described below relates to organs and structures that have importance to pearl production and therefore to the research conducted in this study. Like other members of genus Pinctada, P. maxima has nearly equivalve shells with less projecting posterior ‘wing’, compared to the genus Pteria, and concentric lines. Small projecting scales may also occur on the external surfaces of shells, particularly in young individuals (Lamprell & Healy, 1997). Colour bands of gold or silver occur in distal region of the nacreous part of the inner shell (Fig. 1.2).
Fig. 1.2. The inner surface of two valves of Pinctada maxima from different individuals representing gold lip pearl oyster (left) and silver-lip pearl oyster (right); arrows indicate lip colour.
Fig. 1.3. A pair of valves of Pinctada maxima showing shell morphology and orientation; ae, anterior ear (auricle); am, adductor muscle scar; bn, byssal notch; li, ligament; ms, pallial muscle scar; nb, nacre border; nl, nacre layer (mother of pearl=MOP); pl, prismatic layer, and um, umbo.
188.8.131.52. The shell
Like other bivalves, Pinctada maxima posses a pair of valves (Fig. 1.3). Both valves are attached with a ligament in the dorsal hinge region. There are no hinge teeth (Strack, 2006). The right valve is usually flatter than the left valve. Each shell valve is composed of three layers: (1) the outer layer is the periostracum or conchiolin layer; (2) the middle layer is the ostracum or prismatic layer; and (3) the inner layer is the hypostracum or nacre (mother of pearl) layer (Fougerouse et al., 2008). The periostracum may help reduce biofouling on the outer shell surface (De Nys & Ison, 2008; Guenther et al., 2006). Unlike the periostracum which is formed mainly from proteins, the prismatic and nacreous layers are composed of different forms of calcium carbonate. The prismatic layer is composed of calcite crystals, while the nacreous layer is built from aragonite. These structures are embedded within an organic matrix framework (Addadi et al., 2006; Bedouet et al., 2001; Checa and Rodriguez- Navarro, 2005; Matsushiro and Miyashita, 2004) composed mainly of protein (Matsushiro et al., 2003).
184.108.40.206 The mantle
The molluscan mantle (Fig. 1.4) has many functions. Besides protecting internal organs, the mantle has also roles in assimilation, respiration, locomotion and reproduction (Simkiss, 1988). In relation to shell formation, the mantle is responsible for producing ions and minerals used in the biomineralisation process (Blank et al., 2003). The bivalve mantle consists of two lobes of tissue that line the inner surfaces of both shell valves. As in bivalves, each mantle lobe in P. maxima can be divided into three zones: the marginal, pallial and central zones (Dix, 1973; Humphrey & Norton, 2005). The central zone covers the soft tissue, the pallial zone is composed primarily of muscular threads used in mantle retraction, while the outer marginal zone splits into three folds: the outer, middle and inner folds, each with specific roles (Fougerouse et al., 2008). Tissue from the pallial zone is used in the cultured pearl production process (Acosta-Salmón, 2004).
Mantle Gill , Adductor Muscle, Gonad, Auricle, Byssal gland Foot
Fig.1.4. Internal anatomy of Pinctada maxima (Jameson)
220.127.116.11 The gonad
The gonad (Fig. 1.4) has an important role in cultured pearl production as it is used as the organ that receives the nucleus and nacre secreting tissue implant (‘saibo’) required for pearl production (Taylor & Strack, 2008). The ripe gonad of male P. maxima is milky white but it is creamy yellow for females. When fully ripe the gonad may occupy one-third of the internal space of the oyster. However, pearl oysters with full gonads are not used for pearl production because space is required to house the nucleus and tissue implant. Because of this, the implantation for cultured pearl production takes place after the spawning period or following a conditioning period, which empties the gonad (see Section 18.104.22.168). Changes in water temperature are the main factor in inducing spawning of pearl oysters in nature (Behzadi et al., 1997; Hernandez-Olalde et al., 2007; Saucedo et al., 2002a; Saucedo & Southgate, 2008).
Article source: Mamangkey, Noldy (2009) Improving the quality of pearls from Pinctada maxima. PhD thesis, James Cook University.
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A pearl necklace is an ageless buy. The main issue with that immortality is that a pearl jewelry once in a while looks present day – rich, truly, yet not current. I acquired my mom’s a couple of times for uncommon events in my teenagers, and constantly looked as if I’d done quite recently that; I’ve stayed away from them from that point forward. I comprehend the interest, obviously – that smooth pearlescence is so complimenting against the skin, they run with most anything, and they truly will keep going forever – yet I have constantly discovered pearls excessively exemplary for my taste.
This made everything the all the more astounding when I built up a longing for the round pearl’s rock’n’roll kin, the rococo pearl. It’s not an acknowledgment I came to alone, obviously – Phoebe Philo helped, with Céline’s turquoise-or agate-studded hoops, however at north of £1,000 they fall tragically out of my financial plan.
Single circle, £240, Sarah and Sebastian; Mizuki realistic bands, £475, Net-a-Porter; Large loops, £358, Apples and Figs
Yet, while genuine pearls positively don’t come shabby, there are reasonable alternatives accessible. Refined pearls cost around a tenth of the cost of characteristic pearls, yet both are “genuine” – with “refined” referencing the human mediation that makes a mollusc make a pearl. In essential terms, size and brilliance decide esteem, however since elaborate just alludes to shape, the kind of pearl will be the principle factor in cost. Tahitian and South Sea forms are certainly in the speculation section, while freshwater florid pearls are similarly moderate.
With respect to style, hoops are the most flexible choice for regular wear, however in the event that you’d truly incline toward an accessory, New York name Mounser has a beautiful gold chain and florid pearl adaptation (£305, mounser.com) that would work for day and night.
Studs, £350, Alighieri; Drop, £180.83, Mounser
The most recent incarnations are positively present day. Band studs have for quite some time been a streetwear staple, so the matching of pearls and circles makes for a fascinating conflict. Sarah and Sebastian’s gold circle is sold as a solitary hoop (Vermeer would endorse) and is sufficiently little to be stacked in the event that you have different ear piercings – I do, and plan to wear it with my blended cluster of little yellow gold and jewel loops and studs.
Annoushka offers pearl charms that can be added to circles as of now in your adornments box. For bigger proclamation styles, Alighieri and Mounser both have deviated choices, and Apples and Figs have added precious stones to baroques. Coleman Douglas and Molo Me have more great alternatives, and got the attention of design editorial manager Caroline Leaper as she strolled past my PC screen – they’ll be ideal for her approaching wedding.
By and by, I intend to wear my pearls in a considerably more easygoing setting, and absolutely not spare them for best. They’ll look awesome with a fresh white shirt at the workplace or a cashmere jumper and pants come the end of the week. Also, they’ll run with pretty much everything, since – while they may be the startling decision – they are pearls, all things considered.
Bagaimana cara mengetahui harta mutiara anda mural atau mahal
Saat ini telah banyak sekali kita temukan informasi mengenai harga mutiara dari berbagai macam sumber baik itu dari web site, instagram, facebook, atau media sosial lainnya. Bagaimanakah kita tahu bahwa harga mutiara yang akan kita beli adalah berharga masut akal, murah atau mahal ?
Berikut ini adalah beberapa faktor yang akan menjelaskan keypada kita apakah harga mutiara yang akan kita beli tersebut masuk akal :
1. Kilau Mutiara
Kilau Mutiara adalah faktor yang cukup bisa menjadi faktor penentu utama didalam menentukan harga mutiara tersebut. Semakin mutiara itu memiliki kilau yang lebih bercahaya maka akan semakin mahal harga mutiara tersebut, sebaliknya semakin buram kilaunya maka aka semakin murah.
2. Nacre Mutiara
Nacre adalah lapisan enzim yang dikeluarkan oleh kerang untuk melingkupi inti dari mutiara pada saat mutiara tersebut terbentuk. Dalam hal ini semakin tebal nacre, maka akan semakin mahal harganya. Sebaliknya apabila nacre nya tipis, maka akan semakin murah lah harganya. Amati ketebalan nacre dari kilau cahaya yang dipantulkan oleh sinar yang mengenai permukaan mutiara itu. Semakin tebal nacre maka akan semakin berkilauan, sebaliknya semakin tipis nacre maka akan semakin buram permukaan mutiara tersebut.
3. Mulusnya permukaan mutiara
Mutiara akan semakin mahal jika permukaan mutiara tersebut sangat mulus. Semakin sempurna permukaannya maka akan semakin bernilai harga mutiara tersebut. Mutiara yang memiliki permukaan tidak mulus dalam hal ini memiliki banyak titik, banyak pori-pori, banyak urat varises, maka akan semakin menurunkan kwalitas mutiara tersebut sehingga akan berefek pada harga jualnya yang murah.
Permukaan yang tidak mulus ini data terjadi dikarenakan oleh faktor alam, misalnya :
Salinitas (tingkat asin air laut)
Arus air laut
Gelombang air laut
Kejernihan air laut
Parasit atau virus yang beard dalam tubuh kerang
Perlawanan dari tubuh kerang terhadap zat asing yang masuk kedalam tubuh kerang tersebut
Tiga faktor utama tersebut adalah harus anda perhatikan pada saat anda membeli mutiara agar harganya sesuai dengan kwalitasnya.