diamond

THE MINERAL DIAMOND

• Chemistry: C, Elemental Carbon
• Class: Native Elements
• Subclass: Non-metallics
• Group: Carbon
• Uses: usually as a gemstone and abrasive, also scientific uses.

Diamond is the ultimate gemstone, having few weaknesses and many strengths. It is well known that Diamond is the hardest substance found in nature, but few people realize that Diamond is four times harder than the next hardest natural mineral, corundum (sapphire and ruby). But even as hard as it is, it is not impervious. Diamond has four directions of cleavage, meaning that if it receives a sharp blow in one of these directions it will cleave, or split. A skilled diamond setter and/or jeweler will prevent any of these directions from being in a position to be struck while mounted in a jewelry piece.

As a gemstone, Diamond's single flaw (perfect cleavage) is far outdistanced by the sum of its positive qualities. It has a broad color range, high refraction, high dispersion or fire, very low reactivity to chemicals, rarity, and of course, extreme hardness and durability. Diamond is the April Birthstone.

In terms of it's physical properties, diamond is the ultimate mineral in several ways:

• Hardness: Diamond is a perfect "10", defining the top of the hardness scale, and by absolute measures four times harder than sapphire (which is #9 on that scale).
• Clarity: Diamond is transparent over a larger range of wavelengths (from the ultraviolet into the far infrared) than is any other solid or liquid substance - nothing else even comes close.
• Thermal Conductivity: Diamond conducts heat better than anything - five times better than the second best element, Silver!
• Melting Point: Diamond has the highest melting point (3820 degrees Kelvin)
• Lattice Density: The atoms of Diamond are packed closer together than are the atoms of any other substance
• Tensile Strength: Diamond has the highest tensile strength of any material, at 2.8 gigapascals. However, that does not quite translate into the strongest rope or cable, as diamond has cleavage planes which support crack propagation. The strongest ropes can likely be made from another material, carbon nanotubes, as they should not suffer from the effects of cracks and break. Still, if a long, thin, perfect crystal of diamond could be manufactured, it would offer the highest possible pulling strength (in a straight line - don't try to tie it in a knot!)
• Compressive Strength: Diamond was once thought to be the material most resistant to compression (the least compressible). It is the material that scientists use to create the greatest pressures when testing matter. However, the rare metal Osmium has recently been shown to be even less compressible (although it is not as hard as diamond). Diamond has a bulk modulus (reciprocal of compressibility) of 443 GigaPascals (GPa). The bulk modulus of the metal osmium has recently been found to be 476 GPa, about 7% greater than diamond.

Diamond is a polymorph of the element carbon. Graphite is another polymorph. The two share the same chemistry, carbon, but have very different structures and properties. Diamond is hard, Graphite is soft (the "lead" of a pencil). Diamond is an excellent electrical insulator, Graphite is a good conductor of electricity. Diamond is the ultimate abrasive, Graphite is a very good lubricant. Diamond is transparent, Graphite is opaque. Diamond crystallizes in the Isometric system and graphite crystallizes in the hexagonal system. Somewhat of a surprise is that at surface temperatures and pressures, Graphite is the stable form of carbon. In fact, all diamonds at or near the surface of the Earth are currently undergoing a transformation into Graphite. This reaction, fortunately, is extremely slow.

http://www.galleries.com/minerals/elements/diamond/diamond.htm

Rutile

THE MINERAL RUTILE

• Chemistry: TiO2, Titanium Oxide
• Class: Oxides and Hydroxides
• Group: Rutile
• Uses: Ore of titanium, pigment and as an ornamental stone when in clear quartz

Rutile is an interesting, varied and important mineral. Rutile is a major ore of titanium, a metal used for high tech alloys because of its light weight, high strength and resistance to corrosion. Rutile is also unwittingly of major importance to the gemstone markets. It also forms its own interesting and beautiful mineral specimens.

Microscopic inclusions of rutile in quartz, tourmaline, ruby, sapphire and other gemstones, produces light effects such as cat's eye and asterisms (stars). A beautiful stone produced by large inclusions of golden rutile needles in clear quartz is called rutilated quartz. Rutilated quartz is sometimes used as a semi-precious stone and/or for carvings. This stone is produced because at high temperatures and pressure, n(SiO2)-n(TiO2) is in a stable state but as temperatures cool and pressure eases the two separate with rutile crystals trapped inside the quartz crystals.

Twinning is common in rutile crystals, with a cyclic twin forming that is comprised of six or even eight "twins" arranged in a circle. A Rutile Star is a formation of crystals of rutile in a six rayed orientation. The crystals grow off of a hematite crystal and the orientation is caused by its six rhombic faces.

physical characreristic

• Color is black or reddish brown in large thick crystals or golden yellow or rusty yellow as inclusions or in thin crystals.
• Luster is adamantine to submetallic.
• Transparency: Crystals are transparent in rather thin crystals otherwise opaque.
• Crystal System is tetragonal; 4/m 2/m 2/m
• Crystal Habits include eight sided prisms and blocky crystals terminated by a blunt four sided or complex pyramid. The prisms are composed of two four sided prisms with one of the prisms being dominant. Crystals with some twins forming hexagonal or octahedral circles. A very common habit is thin acicular needles (especially as inclusions in other minerals) or as blades.
• Cleavage is good in two directions forming prisms, poor in a third (basal).
• Fracture is conchoidal to uneven.
• Hardness is 6 - 6.5
• Specific Gravity is 4.2+ (slightly heavy)
• Streak is brown
• Other Characteristics: Striations lengthwise on crystals, high refractive index (2.63) gives it a sparkle greater than diamond (2.42).
• Associated Minerals are quartz, tourmaline, barite, hematite and other oxidessilicates. and
• Notable Occurrences include Minas Gerias, Brazil; Swiss Alps; Arkansas, USA and some African locallities.
• Best Field Indicators are crystal habit, streak, hardness, color and high index of refraction (luster).

http://www.galleries.com/Minerals/Oxides/RUTILE/RUTILE.htm

d block elements

http://chemistry.semo.edu/crawford/ch186/lectures/ch20/slide4.html

what are zeolites?

Zeolites are microporous crystalline solids with well-defined structures. Generally they contain silicon, aluminium and oxygen in their framework and cations, water and/or other molecules wthin their pores. Many occur naturally as minerals, and are extensively mined in many parts of the world. Others are synthetic, and are made commercially for specific uses, or produced by research scientists trying to understand more about their chemistry.

Because of their unique porous properties, zeolites are used in a variety of applications with a global market of several milliion tonnes per annum. In the western world, major uses are in petrochemical cracking, ion-exchange (water softening and purification), and in the separation and removal of gases and solvents. Other applications are in agriculture, animal husbandry and construction. They are often also referred to as molecular sieves.

Adsorption and Separation

The shape-selective properties of zeolites are also the basis for their use in molecular adsorption. The ability preferentially to adsorb certain molecules, while excluding others, has opened up a wide range of molecular sieving applications. Sometimes it is simply a matter of the size and shape of pores controlling access into the zeolite. In other cases different types of molecule enter the zeolite, but some diffuse through the channels more quickly, leaving others stuck behind, as in the purification of para-xylene by silicalite.

Cation-containing zeolites are extensively used as desiccants due to their high affinity for water, and also find application in gas separation, where molecules are differentiated on the basis of their electrostatic interactions with the metal ions. Conversely, hydrophobic silica zeolites preferentially absorb organic solvents. Zeolites can thus separate molecules based on differences of size, shape and polarity.

Ion Exchange

The loosely-bound nature of extra-framework metal ions (such as in zeolite NaA, right) means that they are often readily exchanged for other types of metal when in aqueous solution. This is exploited in a major way in water softening, where alkali metals such as sodium or potassium prefer to exchange out of the zeolite, being replaced by the "hard" calcium and magnesium ions from the water. Many commercial washing powders thus contain substantial amounts of zeolite. Commercial waste water containing heavy metals, and nuclear effluents containing radioactive isotopes can also be cleaned up using such zeolites.

the process of sea cave forming

A sea cave, also known as a littoral cave, is a type of cave formed primarily by the wave action of the sea. The primary process involved is erosion. Sea caves are found throughout the world, actively forming along present coastlines and as relict sea caves on former coastlines. In places like Thailand's Phang Nga Bay, solutional caves have been flooded by the rising sea and are now subject to littoral erosion.

Some of the best-known sea caves are European. Fingal's Cave, on the Scottish island of Staffa, is a spacious cave some 70 m long, formed in columnar basalt. The Blue Grotto of Capri, although smaller, is famous for the apparent luminescent quality of its water, imparted by light passing through openings underwater. The Romans built a stairway in its rear and a now-collapsed tunnel to the surface. The Greek islands are also noted for the variety and beauty of their sea caves. Numerous sea caves have been surveyed in England, Scotland, and in France, particularly on the Normandy coast. The largest sea caves are found along the west coast of the United States and in the Hawaiian islands.

Formation

Sea cave formation along a fault

Sea cave formation along a dike

Sea cave collapse

The "belvedere" watching place in the north Sardinia Nereo Cave

Littoral caves may be found in a wide variety of host rocks, ranging from sedimentary to metamorphic to igneous, but caves in the latter tend to be larger due to the greater strength of the host rock.

In order to form a sea cave, the host rock must first contain a weak zone. In metamorphic or igneous rock, this is typically either a fault as in the caves of the Channel Islands of California, or a dike as in the large sea caves of Kauai, Hawaii’s Na Pali Coast. In sedimentary rocks, this may be a bedding-plane parting or a contact between layers of different hardness. The latter may also occur in igneous rocks, such as in the caves on Santa Cruz Island, California, where waves have attacked the contact between the andesitic basalt and the agglomerate.

The driving force in littoral cave development is wave action. Erosion is ongoing anywhere that waves batter rocky coasts, but where sea cliffs contain zones of weakness, rock is removed at a greater rate along these zones. As the sea reaches into the fissures thus formed, they begin to widen and deepen due to the tremendous force exerted within a confined space, not only by direct action of the surf and any rock particles that it bears, but also by compression of air within. Blowholes (partially submerged caves that eject large sprays of sea water as waves retreat and allow rapid re-expansion of air compressed within), attest to this process. Adding to the hydraulic power of the waves is the abrasive force of suspended sand and rock. Most sea-cave walls are irregular and chunky, reflecting an erosional process where the rock is fractured piece by piece. However, some caves have portions where the walls are rounded and smoothed, typically floored with cobbles, and result from the swirling motion of these cobbles in the surf zone.

True littoral caves should not be confused with inland caves that have been intersected and revealed when a sea cliff line is eroded back, or with dissolutional voids formed in the littoral zone on tropical islands (see Speleogenesis: Coastal and Oceanic Settings). In some regions, such as Halong Bay, Vietnam, caves in carbonate rocks are found in littoral zones but were formed by dissolution.

Rainwater may also influence sea-cave formation. Carbonic and organic acids leached from the soil may assist in weakening rock within fissures. As in solutional caves, small speleothems may develop in sea caves.

Sea cave chambers sometimes collapse leaving a “littoral sinkhole”. These may be quite large, such as Oregon’s Devil’s Punchbowl or the Queen’s Bath on the Na Pali coast. Small peninsulas or headlands often have caves that cut completely through them, since they are subject to attack from both sides, and the collapse of a sea cave tunnel can leave a free-standing “sea stack” along the coast. The Californian island of Anacapa is thought to have been split into three islets by such a process.

Life within sea caves may assist in their enlargement as well. For example, sea urchins drill their way into the rock, and over successive generations may remove considerable bedrock from the floors and lower walls. You might not find a big variety of fishes.

[edit] Factors influencing size

Some sea caves empty out at low tide

Most sea caves are small in relation to other cave types. A current compilation of sea-cave surveys Long sea caves of the world shows three over 300 meters, 15 over 200 meters, and 85 over 100 meters in length. In Norway, several apparently relict sea caves exceed 300 meters in length. There is no doubt that many other large sea caves exist but have not been investigated due to their remote locations and/or hostile sea conditions.

Several factors contribute to the development of relatively large sea caves. The nature of the zone of weakness itself is surely a factor, although difficult to quantify. A more readily observed factor is the situation of the cave’s entrance relative to prevailing sea conditions. At Santa Cruz Island, the largest caves face into the prevailing northwest swell conditions—a factor which also makes them more difficult to survey. Caves in well-protected bays sheltered from prevailing seas and winds tend to be smaller, as are caves in areas where the seas tend to be calmer.

The type of host rock is important as well. All of the largest sea caves are in basalt,^{[citation needed]} a strong host rock compared to sedimentary rock. Basaltic caves can penetrate far into cliffs where most of the surface erodes relatively slowly. In weaker rock, erosion along a weaker zone may not greatly outstrip that of the cliff face.

Time is another factor. The active littoral zone changes throughout geological time by an interplay between sea-level change and regional uplift. Recurrent ice ages during the Pleistocene have changed sea levels within a vertical range of some 200 meters. Significant sea caves have formed in the California Channel Islands that are now totally submerged by the rise in sea levels over the last 12 000 years. In regions of steady uplift, continual littoral erosion may produce sea caves of great height — Painted Cave is almost 40 m high at its entrance.

Finally, caves that are larger tend to be more complex. By far the majority of sea caves consist of a single passage or chamber. Those formed on faults tend to have canyon-like or angled passages that are very straight. In Seal Canyon Cave on Santa Cruz Island, entrance light is still visible from the back of the cave 189 m from the entrance. By contrast, caves formed along horizontal bedding planes tend to be wider with lower ceiling heights. In some areas, sea caves may have dry upper levels, lifted above the active littoral zone by regional uplift.

Sea caves can prove surprisingly complex where numerous zones of weakness—often faults—converge. In Catacombs Cave on Anacapa Island (California), at least six faults intersect. In several caves of the Californian Channel Islands, long fissure passages open up into large chambers beyond. This is invariably associated with intersection of a second fault oriented almost perpendicularly to that along the entrance passage.

http://en.wikipedia.org/wiki/Sea_cave

why cadmium is yellow?

Cadmium pigments are a class of pigments that have cadmium as one of the chemical components. Most of cadmium produced worldwide is used in the production of Ni-Cd Batteries, but about half the remaining consumption, which is about 2,000 tons annually, is used to produce colored cadmium pigments. The principal pigments are a family of yellow/orange/red cadmium sulfides and sulfoselenides. Cadmium yellow is cadmium sulfide (CdS); by adding increasing amounts of selenium, colors ranging from orange to nearly black (the color of cadmium selenide) can be produced. Cadmium yellow is sometimes mixed with viridian to give a bright, pale green mixture called cadmium green.Brilliantly colored, with good permanence and tinting power, Cadmium Yellow, Cadmium Orange, and Cadmium Red are familiar artist colors, but of little use in architectural paints. Their greatest use is in the coloring of plastics and specialty paints which must resist processing or service temperatures up to 300°C. The color-fastness or permanence of cadmium requires protection from a tendency to slowly form carbonate salts with exposure to air. Most paint vehicles accomplish this, but cadmium colors will fade in fresco or mural painting. Cadmium pigments can also color glass and ceramic glazes, not by solution, but colloidal dispersion within the glass. The lenses of red stoplights use this technique.[citation needed]

Cadmium sulfide and a mixture of cadmium sulfide with cadmium selenide are commonly used as pigments in artists' paints. They have an excellent reputation for color permanence although this is partially based on two reasons which are not necessarily directly related to their properties:

1. when introduced, there were hardly any stable pigments in the yellow to red range, especially orange and bright red was very troublesome, when the cadmium pigments replaced e.g. mercury sulfide (the original vermilion), the light-fastness was greatly improved,
2. companies sell the cadmium-containing paints at premium price. Although the pigments are certainly more expensive, the premium price is often not fully justifiable, with reasons more in the marketing area than in the actual raw material cost.

Nowadays, the cadmium pigments have been partially replaced by azo pigments. These are similar in lightfastness to the cadmium colors and have the advantage of both being cheaper and non-toxic. With respect to lightfastness the lemon yellow cadmium pigment is an exception: the azo-variety is highly superior in light-fastness.[dubious – discuss] In some countries, such as Australia, consumer activists such as Michael Vernon were successful in banning the use of cadmium pigments in plastics that could be used for toy manufacture, owing to the toxicity of cadmium.

http://en.wikipedia.org/wiki/Cadmium_pigments

Sea water as a primary minerals

Minerals present naturally in salt from the sea as well as the crystal shape enhance its flavour, therefore the salt can be used more sparingly.Natural Sea Salt use in organic foodstuffs.Natural Salt can be used both for cooking and as a tasty substitute for your current table salt. If you are using coarse salt in a grinder ensure you use a quality salt grinder as natural salt is often slightly more difficult to grind due to its higher moisture content.
Natural Salt contains higher levels of Calcium and Magnesium than normal table salt, as these minerals are also naturally present in sea water. Some people believe that this balance of minerals has beneficial effects on the body.
Sea water containing primary mineral ions: calcium, magnesium, potassium and sodium, the two basic radicals (CO3)-2 and H(CO3)-, and 80+ trace minerals.

Soal Ikatan Metalik

1.10. Satuan sel emas adalah kubus pusat muka (fcc). Berapa jumlah atom menempati

satu-satuan sel emas dan berapa massa satu-satuan sel emas ini?

tiap satuan sel kubus pusat muka

ada 4 atom=(6x1/2)+(8x1/8)= 4

Massa satu-satuan sel emas= 4 atomx197/6,02.10²³ = 1,308.10^-21 g

1.11.Panjang satuan sel emas adalah 0,4079 nm. Hitung volume satu-satuan sel kubus

emas dengan informasi dari soal 1.10 tersebut, hitung pula rapatan teoritis emas

ini!

a=0,4079 nm=0,4079x 10⁻⁷ cm

Volume satu-satuan sel kubus emas

V=a³=(0,4079x10⁻⁷)³ cm³

=6,787x10⁻²³ cm³

Rapatan Emas

Ρ=∑ni x Mi/(Na x V)=4X196,97/(6,02.10²³ x 6,787.10⁻²³)

=19,283 gram/ cm³

1.12.Panjang satuan sel intan terukur 0,3567 nm. Hitung volume satuan sel kubus intan (dalam cm³) dan hitung rapatan teoritis intan jika massa satu atom karbon adalah 12,01 g/mol. Bandingkan hasilnya dengan rapatan intan terukur pada 25⁰C yaitu 3,513 g/ cm⁻³

Volume satuan sel kubus intan (dalam cm³)

V= a³=(0,3567 X 10⁻⁷)³ cm³

=4,538 X 10⁻²³ cm³

Rapatan intan

Jumlah setiap satuan sel intan =(8x1/8) +(6x1/2) +4 atom interior = 8 atom

Ρ=∑ni x Mi/(Na x V)=(8 atom x 12,01 g/mol)/( 6,02.10²³ x 4,538.10⁻²³ )

=3,517 g/ cm³

Diagram tingkat energi

Gambar diagram tingkat energi KF
























Gambar diagram tingkat energi HCl

^ Gold ^

Gold is a chemical element with the symbol Au (from its Latin name aurum) and atomic number 79. It is a highly sought-after precious metal which, for many centuries, has been used as money, a store of value and in jewelry. The metal occurs as nuggets or grains in rocks, underground "veins" and in alluvial deposits. It is one of the coinage metals. Gold is dense, soft, shiny and the most malleable and ductile of the known metals. Pure gold has a bright yellow color traditionally considered attractive.

Gold formed the basis for the gold standard used before the collapse of the Bretton Woods system. The ISO currency code of gold bullion is XAU.

Modern industrial uses include dentistry and electronics, where gold has traditionally found use because of its good resistance to oxidative corrosion.

Chemically, gold is a transition metal and can form trivalent and univalent cations upon solvation. Gold does not react with most chemicals, but is attacked by chlorine, fluorine, aqua regia and cyanide. Gold dissolves in mercury, forming amalgam alloys, but does not react with it. Gold is insoluble in nitric acid, which will dissolve silver and base metals, and this is the basis of the gold refining technique known as "inquartation and parting". Nitric acid has long been used to confirm the presence of gold in items, and this is the origin of the colloquial term "acid test," referring to a gold standard test for genuine value.

http://emaskita.com/index.html

Warna Emas

Untuk mendapatkan perhiasan yang kuat dan warna yang diinginkan, emas murni harus dicampur dengan logam lain. Logam-logam yang biasa digunakan untuk campuran perhiasan emas adalah Tembaga, Perak, Timah Putih, d an Nikel. Disamping menimbulkan kekuatan emas yang berbeda-beda maka campuran logam juga untuk mendapatkan warna yang diinginkan, sehingga dikenal beberapa macam warna perhiasan yang dibuat emas yaitu :

* Emas Merah
Yaitu emas murni dicampur Tembaga
*Emas Kuning
Yaitu emas murni dicampur Perak
*Emas Putih
Yaitu Emas dicampur dengan Timah Sari dan Nikel.

Umumnya kita tahu emas hanya seperti yang disebutkan diatas, Namun karena kemajuan ilmu pengetahuan dan teknologi, maka para peneliti selalu menginginkan hal-hal yang lebih baik dengan mengadakan percobaan-percobaan.

Dalam berbagai percobaan menunjukan bahwa campuran emas murni dengan logam atau beberapa logam tertentu akan menghasilkan beberapa Fancy color yaitu emas hijau, emas biru, ungu dan lain-lain.

- Emas hijau dengan kadar 18 K.
Yaitu campuran antara emas murni 75%, Perak murni 15%. Kadmium 4% dan Tembaga 6%.

-Emas Biru dengan kadar 18 K.
Yaitu campuran antara emas murni 75% dan Besi 25%.

- Emas Jingga dengan kadar 14 K.
Yaitu campuran emas murni 58,33% Perak Murni 6% dan Tembaga 35.67%.

-Emas Coklat dengan kadar 18 K.
Yaitu campuran antara emas murni 75%, Palladium 18,75% dan perak murni 6,25%.

- Emas Abu - abu dengan kadar 18 K.
Yaitu campuran antara emas murni 75%, tembaga 8% dan besi 17%.

-Emas Ungu dengan kadar 18 k.
Yaitu campuran antara emas murni 83,3% dan Aluminium 16.7%.

Warna warna semacam ini memang belum populer di masyarakat, namun tidak menutup kemungkinan pada saatnya nanti akan menjadi populer, namun demikian, ini menunjukan bahwa para pengrajin emas telah maju selangkah dengan adanya warna - warni emas ini.

http://emaskita.com/jenisemas.html

Cara Uji Emas

Untuk Mengenal emas sangatlah mudah, karena memang emas mempunyai warna yang khas, Yaitu warna kuning Emas. Orang yang sudah biasa melihat emas tidaklah sulit untuk menentukan keasliannya, cukup dilihat atau baunyapun sudah mengerti, namun demikian bagi orang awam kelihatannya sangat sulit. Tapi jika pernah memegang emas kemudian kita kenali secara seksama sebentar sajapun akan bisa membedakan antara emas yang asli dengan logam lainnya.

Untuk mengenal emas, kita terlebih dahulu mengenal istilah " kadar " dalam emas. Kadar merupakan tingkat keaslian emas, atau jumlah kandungan kemurnian emas. Kadar emas dinyatakan dalam "karat". Kadar 24 karat dinyatakan sebagai emas murni. Jadi emas kadar 23 karat berarti tingkat kemurniannya adalah 23/24 X 100% atau sekitar 95,8%. Jadi bila Emas Kadar 22 karat dengan berat 15 gram maka kandungan emas murninya = 22/24 x 15 = 13.75 Gram. Jika diketahui emas 16 Karat berat 10 karat berapa kandungan emas murninya?

Ada beberapa metode untuk mengetahui Kadar Emas

1. Dengan Uji Gosok pada Batu, kemudian ditetesi Zat Kimia. Air uji yang digunakan adalah Asam Nitrat, Asam Klorida, Dan Campuran keduanya yang disebut air raja.

2 Pengujian dengan Gold Tester, Yaitu alat yang dapat mendeteksi karat dengan cara menempelkan ujung jarumnya ke perhiasan, alat ini mudah digunakan namun tidak bisa mendeteksi bagian dalamnya.

3. Pengujian dengan berat jenis, setiap benda mempunyai berat jenis atau SG (specifik gravity). Emas dapat dengan mudah dikenali dengan mencari berat jenisnya. Berat jenis adalah Masa Zat itu dibagi Volumenya.
Prosedur pemeriksaan dengan berat jenis adalah pertama kita tentukan berat emas kering ( ditimbang diatas timbangan ), kemudian kita tentukan berat emas jika ditimbang dalam air ( Berat Basah). Berat kering - Berat Basah = Volume. Jadi Berat jenis = berat kering/(berat kering-berat basah). Setelah kita tahu Berat jenisnya kita tinggal lihat tabel untuk mengetahui karatasenya.

http://emaskita.com/caraujiemas.html

warna emas kuning keemasan dan tembaga merah tembaga, mengapa?

Emas berwarna kuning disebabkan oleh frekuensi plasmon emas yang terletak pada julat penglihatan, mengakibatkan warna merah dan kuning dipantulkan sementara warna biru diserap.
Hanya koloid perak mempunyai interaksi yang sama terhadap cahaya, tetapi dalam frekuensi yang lebih pendek, sehingga menyebabkan warna koloid perak menjadi kuning
Sedang untuk tembaga yaitu tembaga ketika sedikit melepaskan takat leburnya, mengekalkan warna kilauan merah jambu apabila cahaya mencukupi sehingga tembaga berwarna merah, selain itu tembaga memantulkan cahaya merah dan jingga dari spektrum cahaya. Tembaga memiliki ciri warnanya karena struktur jalurnya yaitu memancarkan cahaya merah dan jingga dan menyerap frekuensi-frekuensi lain dalam spektrum tampak.