简单
处理中...
What Is The Difference With Crazing to Crack In An Opal?
与蛋白石裂纹有什么不同?
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处理中...

cracked opalMany opal cutters will sell stones that have cracks or crazing in their opals. There is a major difference between the two and we will show you what it is. While there is nothing wrong with buying an Opal that is crazed or cracked it is important that the buyer is made aware before the purchase. If your Opal does have fracture lines in it or it has crazed do not put it in an ultrasonic cleaner as it may destroy the Opal.

CRACKS

cracked opal cracked opal

A crack can be a minor or major fault line. It can be on the surface or internal. If you see a line inside the opal and it reflects light then it is a crack in the stone. External cracks will decrease the value / price more than internal cracks.

Internal cracks have been shown to be stable and not continue to grow. Some Opal miners have stones with cracks inside them that have had no movement. External crack lines in a polished opal can be cut out but obviously this decreases the size and value of the Opal.

Cracked opals do not necessarily mean that they will fall apart. Many cracked opals will hold but the biggest problem is if an opal is cracked and in a ring, the everyday wear and tear and knocks will break the Opal. Many cracked opals are set as pendants for this reason and are able to be worn most of the time.

CRAZING

crazed opal

Crazing looks like multiple crack lines. Crazed opal is mostly kept as specimens or collectors pieces. They are not recommended for use in Jewelry. Crazed opals can be treated with Opticon which stabilises the Opal.

opal with inclusions

The image above is an Ethopian Opal with an inclusion. Notice there is no light reflection.

Inclusions are not cracks. Many opals contain natural inclusions. These can be air bubbles, vegetation matter and even potch.

AUSTRALIAN OPAL

Most Australian opal is very stable with black opal [N1] considered the most stable due to its smaller molecules. Generally Australian Opal that displays a crack is set at 10-20% of the value of a stable opal of similar qualities. It is estimated only around 1-3% of Australian opals crack but some opal fields are more susceptible than others.

Most Australian Opals contain 3-5% water. Generally the deeper the miner digs the more water content the Opal will have. Mines at Lighting Ridge go down to about 30 meters and the miner can gauge how stable the Opal is. As the potch goes from tough dry material to soggy wet potch then it is an indication of stable material. When they go deeper and the miner knows that this opal will obviously have more water content.

Most Australian opals are non porous and therefore they do not absorb water.

POTCH LINES

opal with potch lines

Some opals may show veins or spider web lines. These are not cracks but potch lines. It is easy for the cutter to check as crack lines reflect light but potch lines do not. Potch lines do decrease the value of the opal depending on the severity of lines. They do not generally effect the stability of the opal.

ETHIOPIAN OPAL

ethiopian opal with crack ethiopian opal with crack ethiopian opal with crack

Ethiopian opal is a Hydrophane opal. Hydrophane opal absorbs water. When Ethiopian opal is dehydrated the base is more opaque. when the opal is hydrated it becomes more transparent. Transition time from hydrated to dehydrated can vary from minutes to days but most Opals do transition in a few hours.

FRACTURE TESTING ETHIOPIAN OPAL

Gemstones have been fractured or cleavage tested for centuries to test parting or cleavage in rough material. All major carving or cutting centres fracture test material before cutting or carving.

Even before modern testing techniques were invented rough material was still tested. During winter a wood fire would warm up a room and cold water was splashed repeatedly on the rough.

Today this basic process is still used for opals by soaking the opals in water and drying them in a warm but not hot environment. This processes can be repeated several times before the cutting process starts. Some opal with a small crack line will sometimes expand under water.

This process tests the stress points and cracks will appear on the weakest cleavage point. The opal is now ready for cutting and polishing to remove any visible cracks.

Fractures or crazing and cracks can appear as:

  • granular sugary patterns
  • smooth even breaks
  • rough edged irregular breaks

Cutters obviously make decision to cut an opal after it has been fractured tested as to observe which side of the opal the fracture occurs on. This involves great skill and a professional cutter will cut according to the directions that have opened up when the fracture is complete.

It takes a cutter many years of experience to understand the best approach to cutting an opal. Master opal cutters will charge a percentage cutting fee for top stones from 3 to 5% and in most cases this is worth paying!

OPTICON STABILIZATION

Opticon is the most common form for stabilising opal. Immerse the stones in a canning style jar filled with enough Opticon to cover the stones and tighten the lid so water can not escape. Condensation can turn the resin cloudy.

  • Place the jar in a ordinary slow cooker filled with enough water so the jar dose not float.
  • Turn the heat up to 150-170 degrees Celsius (302 - 338 Fahrenheit)
  • use a thermometer to check the temperature. We recommend using a kitchen meat thermometer.
  • Cook for 24 hours
  • Strain off the excess resin and place on tinfoil

Use a vacuum machine like the ones used to vacuum food bags. This sucks the air out of the bag.

  • Vacuum for at least one hour.
  • Using an artist style brush paint the stone with a weak mixture [40 to 1] of resin and hardener and re vacuum for 15 minutes.
  • Remove any excess moisture with a acetone cloth.
  • When the stones are no longer tacky polish or re-polish

opticon opal treatmentopticon opal treatment

This 54.7 carat Harlequin pattern opal was sold for over $1,100. When it was cut 5 years ago it displayed crazed lines. The owner treated the stone with Opticon and sold it for around 10% of its value if it was untreated.

GLUES

You can also coat the stone with super glue and heat it under strong lights. The glass like covering over the stone gives it stability while it is polished.

BOULDER OPAL

Boulder opal is mostly formed on an ironstone backing and is stable. This ironstone can be A deep brown chocolate color to sandy ironstone with a light brown colour. Ironstone does help to keep the opal stable. Some crack lines may appear at a 45% degree angel but the opal can still be stable. Some boulder crystal opal may also display cracks. Koroit and Yowah opal fields are considered stable.

boulder opal boulder opal

MEXICAN OPAL

Most Mexican opal is stable. Crazed or cracked opals can occur when the potch and opal cut in one piece as each has different pressure threshold.

mexican opal

U.S.A. OPALS

USA Opals are generally not considered to be stable and opals are mostly made in to Triplets or stabilised. USA opals tend to craze as water content can go up to 14%

BRAZILIAN OPALS

These are generally considered stable as the water content is mostly less than 5%. The opals are semi translucent to white translucent.

HONDURAN OPAL

Honduras opal on matrix is considered stable but some crystal formed on matrix may display crack lines

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破裂的蛋白石许多蛋白石切割机会出售在蛋白石上有裂缝或裂纹的石头。两者之间存在重大差异,我们将向您展示它是什么。虽然购买疯狂或破裂的蛋白石没有任何问题,但买家在购买之前必须知道这一点很重要。如果您的蛋白石确实有裂缝线或它有裂纹,请不要将其放入超声波清洁器,因为它可能会破坏蛋白石。

裂纹

破裂的蛋白石破裂的蛋白石

裂缝可以是次要或主要断层线。它可以在表面上或内部。如果你在蛋白石内部看到一条线并且它反射光线那么它就是石头上的裂缝。外部裂缝会比内部裂缝更能降低价值/价格。

内部裂缝已被证明是稳定的并且不会继续增长。一些蛋白石矿工的石头内部有裂缝,没有任何移动。抛光蛋白石中的外部裂缝线可以被切除,但显然这会降低蛋白石的尺寸和价值。

破碎的蛋白石并不一定意味着它们会崩溃。许多破碎的蛋白石将会存在,但最大的问题是如果蛋白石破裂并且环形,日常的磨损和敲击将打破蛋白石。由于这个原因,许多破裂的蛋白石被设置为吊坠,并且大部分时间都可以穿着。

开裂

疯狂的蛋白石

开裂看起来像多条裂缝线。疯狂的蛋白石大多数作为标本或收藏品保存。不建议将它们用于珠宝首饰。可以使用Opticon处理疯狂的蛋白石,稳定蛋白石。

含有夹杂物的蛋白石

上面的图片是包含Ethopian蛋白石。请注意,没有光反射。

夹杂物不是裂缝。许多蛋白石含有天然内含物。这些可以是气泡,植物物质,甚至是potch。

澳大利亚欧泊

大多数澳大利亚蛋白石非常稳定,黑色蛋白石[N1]被认为是最稳定的,因为它的分子较小。通常,显示裂缝的澳大利亚蛋白石设定为具有相似品质的稳定蛋白石的10-20%。据估计,仅约1-3%的澳大利亚蛋白石裂缝,但一些蛋白石领域比其他蛋白质更容易受到影响。

大多数澳大利亚蛋白石含有3-5%的水。一般来说,矿工挖掘的越深,蛋白石的含水量就越多。 Lighting Ridge的矿井下降到约30米,矿工可以测量蛋白石的稳定性。由于potch从坚硬的干燥材料变为潮湿的潮湿的potch,然后它表明材料稳定。当他们走得更深,矿工知道这个蛋白石显然会有更多的含水量。

大多数澳大利亚蛋白石都是无孔的,因此它们不吸水。

POTCH LINES

蛋白石与potch线

一些蛋白石可能会显示静脉或蜘蛛网线。这些不是裂缝,而是potch线。切割器很容易检查,因为裂缝线反射光线但是瓷线不能。 Potch线确实会降低蛋白石的值,具体取决于线条的严重程度。它们通常不会影响蛋白石的稳定性。

埃塞俄比亚欧泊

埃塞俄比亚蛋白石裂缝埃塞俄比亚蛋白石裂缝埃塞俄比亚蛋白石裂缝

埃塞俄比亚蛋白石是一种Hydrophane蛋白石 。 Hydrophane蛋白石吸收水分。当埃塞俄比亚蛋白石脱水时,基部更不透明。当蛋白石水合时,它变得更透明。从水合到脱水的过渡时间可以从几分钟到几天不等,但是大多数蛋白石在几个小时内会转变。

断裂试验埃塞俄比亚欧泊

几个世纪以来,宝石经过断裂或裂解测试,以测试粗糙材料中的分离或裂开。所有主要的雕刻或切割中心在切割或雕刻之前破坏测试材料。

甚至在现代测试技术被发明之前,仍然测试粗糙材料。在冬季,木柴会使房间变暖,冷水会在粗糙的地方反复溅水。

今天,这种基本工艺仍然用于蛋白石,将蛋白石浸泡在水中并在温暖但不热的环境中烘干。在切割过程开始之前,该过程可以重复几次。有些裂纹细小的蛋白石有时会在水下膨胀。

该过程测试应力点,裂缝将出现在最弱的解理点上。蛋白石现在可以进行切割和抛光,以去除任何可见的裂缝。

裂缝或裂纹和裂缝可能表现为:

  • 颗粒状糖模式
  • 平稳甚至休息
  • 粗糙的不规则断裂

切割器显然决定在蛋白石经过断裂测试后切割蛋白石,以观察蛋白石的哪一侧发生断裂。这涉及很高的技巧,专业的刀具将根据骨折完成时打开的方向切割。

需要多年的经验才能了解切割蛋白石的最佳方法。主蛋白石切割工具将收取3%至5%的顶级石头的削减费用,在大多数情况下,这是值得付出的!

OPTICON稳定

Opticon是稳定蛋白石的最常见形式。将石头浸入装有足够Opticon的罐头罐中,盖住石头并拧紧盖子,使水不能逸出。冷凝会使树脂混浊。

  • 将罐子放在装满足够水的普通慢炖锅中,这样瓶子就不会漂浮。
  • 将热量升至150-170摄氏度(302 - 338华氏度)
  • 用温度计检查温度。我们建议使用厨房肉类温度计。
  • 煮24小时
  • 去除多余的树脂并放在锡箔上

使用真空机器,如用于真空食品袋的真空机器。这会吸走袋子里的空气。

  • 吸尘至少一小时。
  • 使用艺术家风格的刷子用弱的混合物[40比1]的树脂和硬化剂涂抹石头并重新真空15分钟。
  • 用丙酮布去除多余的水分。
  • 当石头不再发粘或抛光时

视神经乳蛋白治疗视神经乳蛋白治疗

这款54.7克拉的Harlequin图案蛋白石售价超过1,100美元。当它在5年前被切割时,它显示出疯狂的线条。店主用Opticon对石头进行了处理,如果未经处理,将其售价约为其价值的10%。

胶水

你也可以用超级胶水涂上石头并在强光下加热。覆盖在石头上的玻璃使其在抛光时具有稳定性。

BOULDER OPAL

博尔德蛋白石主要在铁矿石背衬上形成并且稳定。这种铁矿石可以是深棕色巧克力色,也可以是浅棕色的砂质铁矿石。铁石确实有助于保持蛋白石稳定。一些裂纹线可能以45%的角度出现,但蛋白石仍然可以稳定。一些巨石水晶蛋白石也可能会出现裂缝。 Koroit和Yowah蛋白石领域被认为是稳定的。

巨石蛋白石巨石蛋白石

墨西哥欧泊

大多数墨西哥蛋白石都很稳定。当potch和蛋白石切成一片时,每个都有不同的压力阈值,可能会出现裂纹或裂纹蛋白石。

墨西哥蛋白石

美国OPALS

美国蛋白石通常不被认为是稳定的,蛋白石主要是制成三胞胎或稳定的。含水量可达14%时,美国蛋白石往往会热衷

巴西欧泊

这些通常被认为是稳定的,因为水含量大多低于5%。蛋白石半透明至白色半透明。

HONDURAN OPAL

基质上的洪都拉斯蛋白石被认为是稳定的,但在基质上形成的一些晶体可能显示裂缝线

浏览我们的蛋白石

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