11/19/2022 0 Comments Diamond dimensions 243![]() Strong/Very Strong fluorescence requires caution. Medium fluorescence will in most cases have zero to very small influence on colorĪnd overall appearance, however, colorless diamonds can sometimesĮxhibit negative effects and should be examined inĭifferent light conditions before purchasing. GIA grades fluorescence as None, Faint, Medium,įaint fluorescence will have zero effect on color and overall appearance.įluorescence of this type is not an issue and shouldn't be a purchasing factor. One of the biggest benefits ofįluorescent diamonds is that they generally cost less. On the other hand, strong fluorescence can cause a stone (especially in the higher color range D-G) toĪppear hazy or milky under certain light conditions. Lower color range ( H or lower) can benefit from it, as it can make them look whiter, more colorless. Would you want a poorly cut 2.4 carat diamond that is less sparkly and has the same face-up size as an ideal cut 2.2 carat? Probably not.īlue fluorescence can have a positive, negative, or zero effect on a diamond. Adequate size also indicates a good cut, meaning better light performance. So you should make sure it's of adequate size. When a diamond is set in a ring, your eyes will only see the face-up area, Proper face-up size should play an important role when buying a diamond. Twoĭiamonds of the same carat weight can vary greatly in spread, meaning that oneĭiamond can appear larger than the other, even though they weight exactly the same. Weight doesn't equally translate into physical size, especially spread. In short, all is OK, this diamond looks its weight.ĭiamonds are sold by weight (carats), but it's important to understand that Round reference diamond ( see below), this diamond is of adequate (8.7×8.7×5.25mm) is within the normal range for Determination of geometry, such as subsurface pipe shape or depth to top, may be possible in certain circumstances.The face-up size of this 2.43 carat Round Seismic refraction and reflection may provide useful and accurate data but at a significant cost that is not usually justifiable in routine exploration. ![]() Ground magnetics together with either electromagnetics or resistivity are recommended for detailed mapping and multiple intrusion recognition over a potential kimberlite or lamproite. Since separate intrusions may have very different diamond grades, this is of significant importance in the location of initial geological sampling. Complementary surface mapping tools (for example airborne radiometrics, aerial photography, digital topography) have all been of assistance in the exploration process.ĭetailed ground geophysics can usually map out the surface extent of kimberlite or lamproite pipes, and may identify separate intrusions within one kimberlite or lamproite. It is also useful to discriminate targets where other sources of localised magnetic anomalies are common. ![]() AEM assists selection of targets for ground follow-up in areas where kimberlite magnetic anomalies are small. While its cost is a factor of three greater than magnetics, it is particularly effective in detection of weathered or crater facies pipes. Many South African kimberlites are however of Triassic to Cretaceous age, which coincides with a long period of mostly normal polarity, and hence these kimberlites would be of normal polarity even if remanence was predominant.Īirborne electromagnetics (AEM) is extensively used in diamond exploration. It is common that Australian and Canadian lamproites and kimberlites have reversed magnetic polarity. With evidence that a major contribution to kimberlite and lamproite magnetic anomalies is often remanent magnetisation, local anomalies may be of normal or reversed polarity compared to a non-magnetic background. The most cost-effective geophysical reconnaissance technique has been airborne magnetics. They can in most cases accurately detect and map kimberlite and lamproite pipes, whether diatreme or crater fades, and may discriminate separate intrusive phases within an intrusion. ![]() Geophysical techniques are effective in diamond exploration. ![]()
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