Mengenal Jenis Batu Permata

Batu Permata adalah sebuah mineral, batu yang dibentuk dari hasil proses geologi yang unsurnya terdiri dari satu atau beberapa komponen kimia yang mempunyai harga jual tinggi,  diminati oleh para kolektor batu permata. Untuk itu batu permata harus dipoles sebelum dijadikan perhiasan.

Di dunia ini tidak semua tempat mengandung batu permata. Di Indonesia hanya beberapa tempat yang mengandung batu permata antara lain di provinsi Banten yang terkenal dengan Kalimayanya, di Lampung dengan batu jenis-jenis anggur yang menawan dan jenis cempaka, di Pulau Kalimantan dengan Kecubungnya (amethys) dan Intan (berlian). 

Batu permata mempunyai nama dari mulai huruf a sampai huruf z yang diklasifikasikan menurut kekerasannya yang dikenal dengan Skala Mohs dari 1 sampai 10. Permata yang paling diminati di dunia adalah yang berkristal yang selain jenis batu mulia seperti Berlian, Zamrud, Ruby dan Safir, batu-batu akik jenis anggur seperti Biru Langit, bungur atau kecubung yang berasal dari Tanjung Bintang, Lampung saat ini banyak di buru oleh para kolektor karena kualitas kristalnya.

Jenis-jenis batu permata

• Akik
• Akuamarin
• Ametis
• Biduri laut
• Batu biduri Bulan
• Batu Cempaka
• Berlian
• Batu delima
• Chalcedony
• Giok
• Intan atau Berlian
• Kuarsa
• Mutiara
• Mata kucing
• Pirus
• Safir
• Zamrud
• Ruby
• Opal
• Spinel
• Bloodstone
• Tashmarine
• Quattro

Batu kecubung atau ametis merupakan jenis batuan mineral kuarsa. Batu kecubung merupakan batu lahir bagi seseorang yang lahir di bulan Februari. Batu kecubung biasanya berwarna ungu sampai merah muda. Dalam sejarah, ungu merupakan warna yang digunakan oleh raja, ratu, dan anggota keluarga kerajaan lain. Karena itulah, para penguasa sering memiliki berlian yang terbuat dari batu kecubung.

Intan atau lebih dikenal Berlian adalah mineral yang secara kimia merupakan bentuk kristal, atau alotrop, dari karbon. Intan terkenal karena memiliki sifat-sifat fisika yang istimewa, terutama faktor kekerasannya dan kemampuannya mendispersikan cahaya. Sifat-sifat ini yang membuat intan digunakan dalam perhiasan dan berbagai penerapan di dalam dunia industri.

Intan terutama ditambang di Afrika tengah dan selatan, walaupun kandungan intan yang signifikan juga telah ditemukan di Kanada, Rusia, Brasil, dan Australia. Sekitar 130 juta "carat" (26.000 kg) intan ditambang setiap tahun, yang berjumlah kira-kira 9 miliar dollar Amerika Serikat. Selain itu, hampir empat kali berat intan dibuat di dalam makmal sebagai intan sintetik (synthetic diamond).

Batu delima adalah sejenis mineral silikat. Terdapat sejumlah jenis batu delima yang berbeda, tergantung pada logam yang dikandungnya. Kristal batu delima yang ditemukan seringkali berukuran besar dan terlihat cantik. Warna batu delima paling umum merah atau ungu, namun bisa juga ditemukan dalam berbagai warna dan sering digunakan sebagai perhiasan. Di Amerika Serikat, batu delima adalah batu zodiak bagi orang-orang yang lahir di bulan Januari. Kehadiran batu ini di suatu daerah menunjukan disekitar tempat tersebut terdapat intan.

Chalcedony /kælˈsɛdəni/ adalah bentuk kriptokristalin dari silika, terdiri dari mineral kuarsa dan moganit yang saling bertumpuk.^[2] Kuarsa dan moganit merupakan mineral silika, namun kuarsa memiliki struktur trigonal sedangkan moganit bersifat monoklinik. Struktur kimia dari chalcedony adalah SiO₂.

Nama chalcedony berasal dari bahasa Latin chalcedonius (atau calchedonius). Istilah ini pertama kali ada pada karya Pliny the Elder, Naturalis Historia untuk menyebut batuan Jaspis yang transparan.^[3] Istilah ini kemungkinan terinspirasi dari nama kota Chalcedon di Asia Kecil.^[4] Namun istilah khalkedon (χαλκηδών) juga muncul dalam Book of Revelation.^[5]

Giok atau jade adalah sejenis batu "permata hijau" adalah salah satu dari jenis batu permata yang di dalamnya terdiri dari banyak unsur mineral yang telah ditemukan dan digunakan oleh bangsa timur selama beribu-ribu tahun lalu.

Pada saat ini batu giok banyak yang berasal dari daerah Tibet, Tiongkok dan Birma sebagai komoditas ekspor. Giok juga dipercaya berkhasiat membuat ketenangan, kegembiraan dan kesehatan, keselamatan.

Selama perjalanan sejarah setelah ditemukan, giok telah dikenal sebagai asesoris dan perhiasan selama ribuan tahun yang lalu oleh peradaban manusia. Bahkan juga diagungkan sebagai "batu penyelamat" bahkan sebagai "batu kesehatan" oleh suku-suku bangsa di Asia Timur dan di benua Afrika ataupun Amerika termasuk oleh suku Maya dan Inca.

Bahkan dalam dunia medis dewasa ini juga dipercaya dapat meningkatkan kesehatan yang juga telah dipakai dalam peradaban manusia pada ribuan tahun lalu. Hal ini banyak tercatat dalam banyak buku kesehatan kuno dan diakui sebagai salah satu sumber energi alam. Dalam dunia kesehatan, batu ini banyak digunakan untuk meningkatkan sirkulasi darah, anti penuaan dini, meningkatkan kekebalan tubuh dan menghilangkan keletihan. Batu giok juga banyak dipakai pada saat terapi pijat ceragem. Selain itu dalam penyelidikan menunjukkan bahwa batu giok mengandung banyak elemen penting seperti kalsium, potasium, besi dan magnesium.

Batu giok menjadi batu yang paling diminati dalam hal perhiasan, medis dan juga keunikannya sehingga batu ini juga mempunyai banyak model tergantung pada saat batu itu diasah dan dibentuk.

Dalam sejarahnya, batu giok adalah satu-satunya jenis batu permata yang diasah dan dibentuk dalam banyak ukuran dan model. Giok diasah dan dibentuk mulai dari seukuran meja, patung besar hingga patung kecil, liontin, anting, cincin hingga sebesar kancing. Bentuknya juga bermacam-macam, mulai dari yang berbentuk patung Buddha, patung naga dan patung lainnya, juga berbentuk kotak, lonjong, oval, persegi tiga hingga persegi banyak. Selain bentuknya, warna dari giok pun beraneka ragam, mulai dari putih, kuning, merah hingga yang paling populer berwarna hijau.

Mirah delima, merah delima, atau batu Rubi adalah batu permata berwarna merah yang dapat bervariasi antara merah muda hingga merah darah dan merupakan salah satu jenis dari mineral korundum (aluminium oksida). Warnanya terutama disebabkan oleh kromium. Namanya berasal dari buah delima yang isinya berwarna merah. Rubi alami sangat jarang, tetapi rubi buatan dapat difabrikasi dengan cukup murah. Rubi dianggap merupakan salah satu dari empat batu berharga bersama dengan safir, zamrud, dan intan.
Harga batu rubi terutama ditentukan oleh warna. Warna merah paling berkilau dan paling bernilai dapat berharga sangat tinggi melampaui rubi lain dengan mutu yang sama. Setelah warna, berikutnya adalah kejernihan: batu yang jernih menandakan harga tinggi.

Safir (Bahasa Ibrani: ספּיר sapir) adalah bentuk kristal tunggal aluminium oksida (Al₂O₃), suatu mineral yang dikenal sebagai korundum. Safir dapat ditemukan secara alami sebagai batu permata atau difabrikasi pada boule kristal besar untuk berbagai keperluan, termasuk komponen optik inframerah, permukaan jam, jendela yang kuat, dan wafer untuk deposisi semikonduktor seperti nanorod GaN.
Kelompok korundum termasuk aluminium murni. Sejumlah kecil unsur lain seperti besi, titanium, dan kromium memberikan warna biru, kuning, merah muda, ungu, jingga, atau kehijauan terhadap safir. Safir termasuk semua variasi kualitas mineral korundum kecuali yang memiliki warna merah jenuh penuh, yang dikenal sebagai rubi.

Sapphire Price

Sapphire (Greek: σάπφειρος; sappheiros, 'blue stone', which probably referred instead at the time to lapis lazuli) is a gemstone variety of the mineral corundum, an aluminium oxide (α-Al₂O₃). Trace amounts of other elements such as iron, titanium, chromium, copper, or magnesium can give corundum blue, yellow, purple, orange, or a greenish color. Chromium impurities in corundum yield a pink or red tint, the latter being called a ruby.

Commonly, sapphires are worn in jewelry. Sapphires may be found naturally, by searching through certain sediments (due to their resistance to being eroded compared to softer stones) or rock formations. They also may be manufactured for industrial or decorative purposes in large crystal boules. Because of the remarkable hardness of sapphires—9 on the Mohs scale (the third hardest mineral, right behind diamond at 10 and moissanite at 9.25 on the Mohs scale)—and of aluminium oxide in general, sapphires are used in some non-ornamental applications, including infrared optical components, such as in scientific instruments; high-durability windows; wristwatch crystals and movement bearings; and very thin electronic wafers, which are used as the insulating substrates of very special-purpose solid-state electronics (especially integrated circuits and GaN-based LEDs).

Sapphire Price:

A question we frequently hear from customers is, "How much is a good sapphire?" It's not an easy question to answer because there are many different grades and colors of sapphire. Prices depend on carat weight as well. Still, it's a question worth answering, so here is our best attempt to answer it, based on our experience in the market.
Let's start at the lower end of the market and work upwards. The most inexpensive sapphires are carvings, since that's what the industry does with lower grade material that isn't suitable for gemstones. Carvings tend to be priced by the piece rather than the carat, since the work that goes into making them usually exceeds the cost of the material. You'll find small carvings starting at $10-20 per piece.

Next up in price are sapphire cabochons. Material of good color which is not sufficiently transparent to cut in facets is used to create the domed shape known as cabochon (or cab for short). You'll find these most often in blue and green, and they are often available in larger sizes as well, often up to 10 or 20 carats. The price per carat on the cabochons tends to be constant regardless of size, and we often have them at around $10 a carat. They can make some very attractive jewelry that has all the virtues of sapphire at a very affordable price.

You'll also find star sapphires in the cabochon-grade material. Here in Thailand we see several kinds of star sapphires. Our home province of Chanthaburi produces the untreated black and gold star sapphires found nowhere else in the world. We also have blue star sapphires that are diffusion treated with titanium to improve the star effect. Most of the star sapphires sell for around $10 a carat. Rare transparent star sapphires do exist but you'll find them mainly in museums.

Moving to faceted sapphire, the lower priced pieces will either be small sizes (under half a carat), heavily included material, or beryllium-treated. Prices for faceted sapphire start at about $20 a carat and rise according to size and color. In sizes greater than 1 carat you'll find clean beryllium-treated green sapphire at around $75 a carat, and yellow and red-orange pieces at around $100 to $120 a carat. We've noticed that the prices for beryllium-treated sapphire have been rising significantly in the last year.

Prices for heated blue sapphire depend very much on color and clarity. You can expect to pay around $300 a carat for clean pieces in the 1-2 carat size with good color saturation. Prices typically go up substantially for quality sapphire over 2 carats. We've had some excellent 2-2.5 carat blue sapphires at around $400 a carat and recently acquired a 5.09 carat Madagascar sapphire with IF clarity that is priced at around $600 a carat.

It is more difficult to state typical market prices for very fine unheated sapphire, since they are so rare. But we recently acquired two outstanding pieces from the Diego-Suarez mine in northern Madagascar. One piece is a stunning violet blue, 2.62 carats in weight and VVS clarity. It is a beautifully cut round, a shape that typically commands a premium in the market. We priced it at $965, which is probably unusually low for the market. A second unheated piece is a 6.33 carat rich blue with a hint of green, with a clarity grade of IF. It's priced at $5575. Generally you won't find fine unheated sapphire of any size at prices under $1000 a carat.

(source: Gemselect)

Almandine Garnet Stone

Almandine garnet, sometimes referred to as almandite garnet, belongs to the very vast and popular mineral group of garnet. Almandine is the most common of all garnet varieties. Although there are very large amounts of almandine sourced from all over the world, only a small percentage of the stones mined are of gem quality. Most almandine stones are opaque and rough, which means that they are only used for industrial purposes. Garnet stones are often used for sandblasting in the industrial sector.

The word 'garnet' is derived from the Latin word "granatus", which means grain, because many garnet deposits are small grains of red crystals in or on their host rock. The specific name of almandine originates from the name alabandicus which is the name of a stone found in the small town of Alabanda, located in Caria, the second smallest province of Asia Minor. Almandine occurs in a range of reds from dark brownish to purplish red and is a very popular gem choice for jewelers due to the excellent hardness (7.5 on the Mohs scale) and brilliance resulting from its high refractive index. Almandine garnet is often cut en cabochon with convex faces, and these specimens are sometimes referred to as carbuncles. Carbuncle is an old term used to describe any type of red gemstone cabochon. Red gemstone cabochons have historically been used as friendship gems. Garnet is also January's birthstone.

Almandine garnet can be difficult to distinguish between other garnet types by appearance alone, as well as other red stones. Almandine garnet will typically have darker tones compared to other red gems, but top quality specimens do have red colors similar to that of ruby. A strong neodymium magnet will be able help distinguish garnet from other gemstones. Measuring a stone's magnetic susceptibility in collaboration with its refractive index can be used to distinguish specific garnet species and varieties, and it can also determine the percentage of composition in hybrid variety garnets.

Buying Almandine Garnet

Almandine garnet gemstones can be found in many origins and sources including Brazil, India, Madagascar, Sri Lanka and the United States. Smaller deposits exist in Austria and the Czech Republic. Almandine garnet star gemstones are found in India and the United States. Idaho is known to be a very large source for star garnet gems. Amandine found in Sri Lanka is sometimes referred to as Ceylon ruby.

Almandine Garnet Color

Almandine garnet colors can range from pure red, reddish orange and slightly purplish red to dark brownish red. The unique deep red color of almandine is a direct result from the presence of iron.
Almandine garnet with pure, deep red colors are the most desirable and valuable of almandine stones.

Almandine Garnet Clarity and Luster

Almandine garnet has a vitreous luster. Gem quality almandine garnet is translucent, but depending on the cut, some stones may appear to be more translucent to opaque. Most almandine garnet rough is opaque and not considered to be of gem quality. These specimens are typically used for various industrial purposes.

Almandine Garnet Cut and Shape

There are abundant amounts of very large sized almandine garnet crystals, but because of their dark tones, only small to medium sized gems are faceted. When faceted, they are often cut slightly shallow to allow light to pass through them. Some garnet stones when cut en cabochon can display an asterism effect; these are referred to as star garnets. Almandine garnets can be found in a wide variety of shapes and cut styles including round, oval, pear, heart and trillion facet or cabochon stones.
(source:  Gemselect.com)

Ruby Stone

A ruby is a pink to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). The red color is caused mainly by the presence of the element chromium. Its name comes from ruber, Latin for red. Other varieties of gem-quality corundum are called sapphires. The ruby is considered one of the four precious stones, together with the sapphire, the emerald and the diamond. 

Prices of rubies are primarily determined by color. The brightest and most valuable "red" called blood-red, commands a large premium over other rubies of similar quality. After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated. Cut and carat (weight) are also an important factor in determining the price.

Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness. Among the natural gems only moissanite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissonite falling somewhere in between corundum (ruby) and diamond in hardness. Ruby is α-alumina (the most stable form of Al₂O₃) in which a small fraction of the aluminium³⁺ ions are replaced by chromium³⁺ ions. Each Cr³⁺ is surrounded octahedrally by six O^2- ions. This crystallographic arrangement strongly affects each Cr³⁺, resulting in light absorption in the yellow-green region of the spectrum and thus in the red color of the gem. When yellow-green light is absorbed by Cr³⁺, it is re-emitted as red luminescence.^[2] This red emission adds to the red color perceived by the subtraction of green and violet light from white light, and adds luster to the gem's appearance. When the optical arrangement is such that the emission is stimulated by 694-nanometer photons reflecting back and forth between two mirrors, the emission grows strongly in intensity. This effect was used by Theodore Maiman in 1960 to make the first successful laser, based on ruby.

All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics, simulants, or substitutes. Usually the rough stone is heated before cutting. Almost all rubies today are treated in some form, with heat treatment being the most common practice. However, rubies that are completely untreated but still of excellent quality command a large premium.

Some rubies show a three-point or six-point asterism or "star". These rubies are cut into cabochons to display the effect properly. Asterisms are best visible with a single-light source, and move across the stone as the light moves or the stone is rotated. Such effects occur when light is reflected off the "silk" (the structurally oriented rutile needle inclusions) in a certain way. This is one example where inclusions increase the value of a gemstone. Furthermore, rubies can show color changes—though this occurs very rarely—as well as chatoyancy or the "cat's eye" effect.

Factors Affecting Values

Diamonds are graded using criteria that have become known as the four Cs, namely color, cut, clarity and carat weight. Similarly natural rubies can be evaluated using the four Cs together with their size and geographic origin.

Color: In the evaluation of colored gemstones, color is the most important factor. Color divides into three components; hue, saturation and tone. Hue refers to "color" as we normally use the term. Transparent gemstones occur in the following primary hues: red, orange, yellow, green, blue, violet. These are known as pure spectral hues.^[11] In nature there are rarely pure hues so when speaking of the hue of a gemstone we speak of primary and secondary and sometimes tertiary hues. In ruby the primary hue must be red. All other hues of the gem species corundum are called sapphire. Ruby may exhibit a range of secondary hues. Orange, purple, violet and pink are possible.

The finest ruby is best described as being a vivid medium-dark toned red. Secondary hues add an additional complication. Pink, orange, and purple are the normal secondary hues in ruby. Of the three, purple is preferred because, firstly, the purple reinforces the red making it appear richer.^[11] Secondly, purple occupies a position on the color wheel halfway between red and blue. In Burma where the term pigeon blood originated, rubies are set in pure gold. Pure gold is itself a highly saturated yellow. Set a purplish-red ruby in yellow and the yellow neutralizes its complement blue leaving the stone appearing to be pure red in the setting. (wikipedia.org)