DE1927631A1 - Process for changing the color of gemstones - Google Patents

Description

DR-INQ. C.lfL.-INO *. TC. DI PL.-PH YS. O R. DIF'l.- '

HÖGER - LEGAL RIGHT-GRIESSBACH - HAECKER

PATENT LAWYERS IN STUTTGART

1927331

A 37 418 b
May 28, 1969
Iy-3 5

John C. Haynes 12 E. Park Place, Newark Ohio / USA

Process for changing the color of gemstones.

The invention relates to a method for changing the color of gemstones.

A process for coloring diamonds was published around 60 years ago. In this procedure were

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the diamonds are immersed in liquid radium bromide for a long time. The diamonds banded in this way, however, were strong radioactive, even after long exposure to strong nitric acid and potassium chlorate, which is why these Diamonds could not be used as jewelry diamonds. They were practically worthless and were nothing else as a curiosity.

However, there was great interest in coloring gemstones and especially diamonds, which is why attempts were made to irradiate gemstones in a cyclotron. The colors of the gemstones produced in this way ranged from a bluish green to dark yellow tones. However, they had a shielding effect along the border or a dark ring along the edge of the fitting, depending on whether the stones were irradiated from the side or from the top. Stones that have been colored in the cyclotron have a spectrogram with an absorption line of 5,920 angstroms, which is not included in the spectrogram of natural stones that are colored accordingly. The stones colored in the cyclotron also have absorption lines of 4,980 and 5,040 angstroms, the 4,980 line being stronger than the 5040 line. In the case of the green diamonds found in the Hatur, however, the 5040 line is stronger than the 4 980 line. The stones colored in the cyclotron therefore do not have the same color distribution as a natural stone. As a result of these unfavorable results, the coloring of gemstones with the aid of a cyclotron has proven to be unsuitable, since in addition the costs are high and the times available are very limited when there are few cyclotrons.

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ORIGINAL INSPECTED 009837/2070

A 37 41.8 b - 3 -

May 28, 1969

It is also known to color diamonds by placing the stones in a tube and placing them in a nuclear reactor. The stones colored in this way have a 5,920 angstrom line, which natural diamonds do not have, furthermore the lines of 4,980 and 5,040 angstroms are almost equally strong, while in the case of natural diamonds the 5 040 line is stronger than the 4,980 -Line. Since the diamonds in the reactor are exposed to intense radiation, the lattice structure of the diamond is softened, so that the cohesive energy of the diamonds is reduced ^{by about 40 c} / o ■ * ■ by up to 75 ^σ Α. The same decrease in strength occurs with the diamonds treated in the cyclotron as a result of the strong radiation and the Y heats. Since it is difficult to precisely control the irradiation time in a nuclear reactor, the diamonds cannot be colored in predetermined hues, ie the treatment is uneven and not reproducible. Also, diamonds treated in the nuclear reactor tend to turn more yellow than green, and the green stones produced are not very beautiful. However, green stones that are not optimally beautiful are difficult to sell. By treating the stones in the cyclotron and in the nuclear reactor, only a small percentage of stones are obtained that have the desired color, but even then these stones still have noticeable differences compared to the natural stones.

The invention is therefore based on the object of specifying a method for coloring precious stones, the stones after treatment are non-radioactive and indistinguishable from natural stones.

* and the hardness

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May 28, 1969

According to the invention, this is achieved in that the gemstone to be treated is brought into direct contact with granular, radioactive material until the color of the stone has changed, whereupon the stone is removed from the radioactive material and is immersed in a liquid in which the water adhering to the stone j «© .dioalctiv Materialii ² dissolves or is removed.

The stones produced with the aid of the method according to the invention can no longer be distinguished from natural stones. Any desired color or shade can be produced.

The stones are expediently completely surrounded by the radioactive material that emits a certain desired radiation. The radioactive material is expediently a solid which does not sublime or become liquid under the conditions of the treatment. The individual particles of the radioactive material surround all surfaces of the gemstone to be treated. The stone remains embedded in the radioactive, granular material for a certain time, after which it is removed and immersed in a liquid in which the radioactive material that adheres to the surface of the stone is removed. In those cases where

not

the adhesion of the radioactive material / by a film former (fUmformer) is generated, but is in direct contact with the surface of the gemstone, that becomes radioactive material dissolved and removed by an acid, provided that the stone is not attacked by the acid. Preferably the stones are grounded in a series of Acid cleaning baths brought and then rinsed with water. With this treatment, all radioactivity disappears.

Q 0 9 8 3 7/2 0 7 Q BAD ORIGINAL

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May 28, 1969

did so that the remaining radioactivity of the stone far is below the limit prescribed by the US Atomic Energy Commission.

Before immersion in the first acid bath and after Removing the stones from the radioactive material, preferably grounding them to the action of a fine abrasive exposed to physically remove most of the adhering radioactive material in solid form, so that the latter can be more easily recovered. In the case of diamonds, any cheap abrasive can be used including sand can be used. For other gemstones, a finer abrasive such as sebum can be used be desirable.

The treatment is preferably carried out in an airtight chamber with mechanical arms or grippers is provided, which can be actuated from outside the chamber, to place the gemstones in a container that contains the solid radioactive Material, to be brought in and taken out, and to be put into a drum containing an abrasive, such as contains sand, to bring in and take out again, whereupon they are finally placed in an acid bath and can be removed from this again. The acid bath containing the diamonds can be removed from the chamber but preferably the diamonds are removed from the first acid bath and placed in a container, which contains pure acid, which is then taken out of the chamber. The second acid tank is then preferably subjected to ultrasonic vibrations, whereupon the diamonds are removed from this container and transferred to a third one Inlaid acid bath, which is also ultrasonic

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exposed to vibrations, whereupon the diamonds are taken out of this and washed with water and a cleaning agent rinsed v / earth. The stones are then grounded with the aid of a Geiger counter or some other heating device Radioactivity examined and if no radiation is found: is adjustable, the diamond is ready and can be set and used.

The diamonds, when irradiated with alpha rays, contain an emerald green color which can be lightened somewhat by heating to a temperature above about 315 ° C (600 ° P). At a temperature of around 426 ° C (800 ° F) the color can turn into a light green, at around 538 ° C (1000 ° P) into a very light shade, and at temperatures up to around 982 ° C (1800 ° F) increasingly darker gold tones can be achieved. In these cases, if the color is lighter than desired, the stones can be irradiated again according to the above procedure to add a green coloration. If even darker tones are desired, the stones can also be treated again. A one or two-stage post-treatment can achieve very precise color tones, and since the process is very easy to carry out and control, practically all gemstones can be colored in a desired green or yellow tint, regardless of their original color.

The gemstones of the invention do not have any noticeable Residual radioactivity and can therefore be worn and brought into direct contact with the body. The stones can be irradiated by any known type of radiation, including alpha rays, beta rays, gamma rays

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,.,. _s .,, ORIGINAL INSPECTED 009837/2070 ^; -

Γ '1927331

A 37 418 b - 7 -

May 28, 1969

iy-35

len, slow neutrons, fast neutrons, deuterons, Positrons and / or mesons. Practically everyone can Types of gemstones are treated. A preferred embodiment of the invention, however, consists of diamonds To be colored emerald green, the color being indistinguishable from that of the naturally occurring stones. the Diamonds can also be colored in yellow hues.

It has been found that the naturally occurring tints of green diamonds are best matched by a practically pure one Alpha radiation can be generated that is essentially free of gamma or beta radiation. It can, however all charged particles perish with great effect, whereby radiations with gamma rays or with neutrons can also be used, but with less effect. According to the preferred embodiment of the invention treated diamonds have a nicer color than diamonds with Radium can be treated.

Below are some preferred examples of the invention Procedure given:

example 1

A diamond to be colored is placed in a small container containing Am eic ium oxy d of americium-142. The container is arranged in a practically airtight chamber and the diamond is placed in the container with the help of mechanical grippers that are controlled from outside the chamber. The container is shaken sufficiently _;

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'' ·· '1927S31

A 37 41B b - 8 -

May 28, 1969

to embed the diamond in the powdered americium oxide, the particles of which have a grain size of about 0.15 mm. The diamond is in the americium powder more than left for two days and preferably about seven days to two weeks. In the present case, a commercially available Fifty facet diamond embedded in the americium oxide powder for seven days and then through the mechanical Gripper removed from the americium oxide and placed in a glass bowl containing sand. On the shell A lid was put on and the bowl shaken and shaken for several minutes, after which the diamond was removed using the mechanical gripper. The diamond was then placed in a container that was about Contained 25 cbm of concentrated nitric acid, in which it remained for about 15 minutes. After that, the acid was in poured another container and poured the diamond into a second container that concentrated about 25 cbm Contained nitric acid, which was free of radioactivity. The second container with the nitric acid was then taken out removed from the chamber and ultrasonically agitated for about 15 minutes. The second acid bath turned off poured out the container and the diamond poured into a third container, the about 25 cbm concentrated nitric acid which was free of radioactivity, and this container was again ultrasounded for about 15 minutes was vibrated. The third acid bath was then poured out of the container and the diamond in a Beaker poured out. Water was placed in the beaker and the diamond washed to remove the acid. The diamond was then taken out of this water and brushed with more water and detergent to remove any acid, contaminants, etc. The diamond was then measured with the help of a Geiger counter

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May 28, 1969

and it was found that it did not contain any radioactivity.

The pretreated diamond Taat an emerald green color. That The spectrogram of the diamond showed absorption lines 4,980 and 5 040 angstroms, with the 5 040 line being darker, and where the 5,920 line was absent. This spectrogram was therefore identical to your spectrogram of natural diamonds and it was different from that of the stones treated in a cyclotron or in a nuclear reactor. The stone had a luster like the natural diamonds and it did not have the dull appearance of the diamonds, which are treated in a nuclear reactor. The emerald green color of the diamond created as described above was changed to a very bright yellow by placing the diamond in an electrically heated air oven for about one heated to a temperature of about 538 C (1000 F) for half an hour. Before entering the oven the diamond was coated with a paste of boric acid alcohol to prevent oxidation. Each of the removal out of the oven and after cooling, the color of the diamond had changed to a very light yellow. By a Heating to about 315 C (600 F) produces a lighter one Green tint from heating to around 4-26 ° C (800 ° F) a light green color and heating to about 982 ° C (1800 F) gives a golden color.

The diamond treated as described above was a finished, marketable yellow stone. To see if the Color can be made darker, the very light yellow diamond was irradiated again in the same way, for an additional seven days, after which he-

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in the same way as described above, shaken and treated with acid. The diamond was then washed, coated with a paste made of boric acid and heated in an oven to about 982 ° C (18oo ⁰ F) for half an hour, whereby its color changed to a bright gold tone. The gold-colored diamond had the luster and hardness of natural stones colored in the same way, and its hardness was not reduced, as with stones treated in a cyclotron or a nuclear reactor. The stone also contained no detectable radioactivity.

As mentioned earlier, other radioactive materials can be used to color diamonds, such as gamma rays, fast neutrons, deutorons, positrons, etc. at the preferred However, these radiations are not used in the method for producing green or yellow diamonds. In making greener Diamonds are preferred to radioactive substances that emit essentially pure alpha radiation. Suitable materials are e.g. Plutonium 239, Americium 241 and Polonium 210 diluted with an inert, granular material.

However, the substances used should remain in a solid state and not evaporate or become liquid. Polonium evaporates for example at 55 ° C and is therefore expediently not used at room temperature. High melting point salts of polonium 210, such as the sulphates, can, however, be used.

Example 2

A diamond with fifty facets turns into grainy for a fortnight Plutonium oxide embedded in plutonium 239 using the method described above. After washing with nitric acid, as described above, the diamond had

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none, noticeable. s ^tranlun S u * ^{10 it} was green in color, the ^e: iipectrogram corresponding to that of the natural green diamonds.

By using and applying beta radiation, In the general procedure described above, the diamonds can be colored blue.

Example 3

A diamond with fifty facets was embedded in long-grained strontium oxide of strontium 90 fortnight whose K _o rngröße about 0.15 was now, whereupon the diamond to the method described above was purified in accordance with hydrochloric acid. After cleaning, the diamond had no measurable radiation and was blue in color. Other beta emitters can also be used, such as antimony 125, tritrium, irritium 90, cesium 13 ¹ I, cesium 137, barium 139, beryllium 10, cobalt 60, nickel 63, promethium 17, strontium 90, thallium 20 ¹ I, etc. Here, too, the radioactive substances should be in solid form, which have practically no vapor pressure. Any oxide or salt of these substances can also be used. If tritrium is used, it can be used as the hydride of beryllium or aluminum.

Although gamma rays are not a preferred type of radiation for coloring gemstones, gamma emitters can be used in accordance with the above method, with still better results being obtained than when using gamma emitters in accordance with the known methods. Suitable gamma emitters are cobalt 60, cesium 137, iron 55, magnesium 5 ¹ *, mercury 203, barium 133 etc.

In the same way, fast-flying neutrons are not preferred Type of radiation, but when used according to the above procedure they give better and more beautiful stones than with

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May 28, 1969 I y ^ / od1

Use according to the known methods. Suitable materials that emit fast-flying neutrons are obtained when Americium 241, for example in an oxidized state, is added to the mixture. Another source of fast-flying neutrons obtained by a mixture of powdery plutonium 239 and powdery beryllium or by a mixture of powdery Polonium sulphate 210 and beryllium powder.

By using these materials according to the inventive method one also obtains more beautiful stones than after the known procedures.

By using positron radiation according to the invention This method also gives more beautiful stones than when using this radiation according to the "known methods. Suitable." Positron emitters are sodium 22, aluminum 26, lanthanum 138, etc.

However, the invention is not only suitable for coloring diamonds but also for coloring other stones.

Example 4

A two-carat piece of quartz became fourteen in americium oxide 241 Embedded for days using the procedure described in Example 1. After cleaning in the acid baths the stone was gray in color and had no measurable radioactive activity.

Example 5

A topaz was laid in americium oxide 241 for fourteen days according to embedded in the method according to example 1. He had a yellow brown Color and was free of radioactivity after acid treatment.

ORlGiNAL INSPECTED 009837/2070

37 418 b _n 1927531

May 28, 1969

Iy - 133 -

Other stones that can be treated with the method according to the invention are zircon, garnet, corundum, chrysoberyl, spinel, Perodet, Spodomen, Tourmaline and others

It is surprising that gemstones that come in direct contact with a radioactive material can be treated without any residual radioactivity in the stone remains behind. The reasons why stones that have been treated according to the previously known method become radioactive after treatment remained, can - although not yet known - be the following: It is assumed that all gemstones are very small Have cracks or defects in the crystal lattice that are exposed on the surface of the stones, and in many cases these Cracks are associated with contaminating foreign matter. In the case of diamonds, such a contaminating foreign matter can occur Be graphite, which has an amorphous structure that is porous and absorbent. It is also assumed that the hitherto known radium treatment radioactive liquid penetrated into these cracks, which in the subsequent acid treatments never could be completely removed.

In the method according to the invention, however, penetrate the radioactive particles including the dust that is on the surface the radioactive emitter does not accumulate in these cracks, but at most collects at the entrance of the cracks. The said Dust can also be held in place by grease or other films on the surface of the stones. By breaking the connection these particles with the stone, be it a connecting film or the surface of the particles that have penetrated into the cracks somewhat the radioactive material is either dissolved or detached, so that it is removed from the surface of the stone in either case Will get removed. Any remaining radioactive liquid is then replaced by pure liquid long before it

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Iy - 133 -

has the possibility of getting into the cracks in the surface of the gemstones to penetrate. As a result of the differences in concentration, the method according to the invention affects the radioactive one Force directed towards the material, away from the stone, outwards rather than inwards.

It can now also be given the reasons why the invention treated stones have a nicer and better color than the stones treated according to the known methods. With the radium treatment, the gemstone is irradiated with considerable gamma radiation, which penetrates the stone and increases the opacity of the entire stone. Through this the stone loses its chandelier. The gamma radiation also tends to produce the characteristic brown spots that appear in radium-treated stones can be observed.

When the stones are treated in cyclotrons, irradiation takes place largely in one direction, so that some faces of the stone are more colored than others. When the invention Procedure, however, the stones are irradiated evenly from all sides, and when using alpha rays, up to to a depth of several hundredths of a millimeter below the. Surface of the stone. If during the cyclotron EB treatment alpha radiation is used, the parallel irradiation changes the color of the surface unevenly. V / ground in cyclotron treatment If gamma rays or fast-flying neutrons, deutorons etc. are used, the radiation goes through completely through the stone, whereby the stone loses its luster. Besides that these stones show the characteristic 5920 Angstrom absorption line.

During treatment in the nuclear reactor, the stones are also exposed to a large number of radiations that completely affect the stone penetrate, creating the characteristic 5920 Angstrom line gets and loses its luster and hardness.

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Claims (11)

> ί 418 b 'Λ Iy - 133 -49-- XS claims 1. Method of changing the color of gemstones, thereby characterized in that a gem is brought into direct contact with granular, radioactive material and this contact is maintained until the Color of the gem has changed that after that the irradiated Gemstone is taken out of the granular, radioactive material and immersed in a liquid that creates the compound dissolves the radioactive material with the stone. 2. The method according to claim 1, characterized in that the liquid is an acid which dissolves the radioactive material. 3 · The method according to claim 2, characterized in that the surface of the gemstone with a granular abrasive before dipping the stone in the acid. * ». Process according to Claim 2, characterized in that the gemstone is removed from the first acid bath and into the second or subsequent subsequent baths Acid baths are immersed that are free of radioactivity. 5. The method according to claim 1, characterized in that the gemstone on a sufficient high temperature is heated to change color. 6. The method according to claim 5, characterized in that the gemstone is in direct contact nit ^, radioactive material is brought to a to produce further change in color. powdery 009837/2070 May 28, 1969 Iy - 133 - ⁴ ^ " 7. The method according to claim 6, characterized in that the gemstone is again increased to a given temperature is heated to change its color to a desired shade. 8. The method according to claim 1, characterized in that the radioactive material atoms of Contains americium 2Ί1. 9. The method according to claim 7 or 8, characterized that the gem is a diamond. 10. The method according to any one of the preceding claims, characterized in that the to be treated Gemstone is placed in a chamber in which a container is placed that contains a powdered radioactive Material contains that the gem is embedded in the container and in contact with the powdered radioactive material is brought that the irradiated gemstone is taken out of the container and placed in a container with abrasives is brought, which is also arranged in the chamber, that the abrasive over the surface of this gemstone is moved and this is taken out of the abrasive and immersed in a container that contains acid and is also located in the chamber, and that the gem is taken out of the chamber, washed and dried will. 11. The method according to claim 10, characterized in that the container containing the acid, while the gemstone is immersed in the acid, it is vibrated with the help of ultrasound. 009837/2070