Today, let's take a look at one of the many tools that gemologists must take with them to the field. Many might suggest that the loupe is the most valuable instrument anyone in the trade should have. Certainly not because of its monetary value, but rather because convenient magnification is needed in every aspect of the gemstone trade.



Diamonds are graded for clarity based on 10x magnification, so you don't always need a fancy microscope to check the quality of your precious stones. A handy loupe is sometimes most preferable, because during travel, trade shows, sales meetings or wherever you go, it's not very convenient to backpack your gemological microscope.

Gem Loupes are the Most Basic Viewing Instruments to Carry Around With You During Gemstone Buying Trips. They Are Helpful for Grading Diamonds, Identifying Colored Stones, and Even Checking Laser Inscriptions for Report Matching.

A gem loupe is usually made up of three lenses. These three lenses function together to give you the most accurate and undistorted image you can get at a specific magnification level.

We call this loupe a fully corrected triplet loupe. Others may sometimes call it an apochromatic loupe, which means it is both aplanic (corrected for spherical distortion) and achromatic (corrected for color distortion).

There are many "fake" triplet loupes out there that make use of a single lens. You'll notice that these instruments will show you a more distorted view of your gemstone, especially when you observe around the outer edges of the viewing area.


It's always recommended to familiarise yourself with how true gemological loupes showcase a magnified image, so that you know what to look for when buying a new or a replacement loupe.

Using your loupe correctly is also good practice. It shows professionalism, and at the same time makes it easier for you to evaluate stones with more comfort and patience.

To begin, unfold your loupe and use the side of your index finger and tip of your thumb to hold the lens case. Now position the lens in front of your eye (or eyeglass lens) and let the back of your thumb gently press against your cheek. This is just to keep your hand from fidgeting while you use your loupe.

So now, with your other hand holding your tweezers, gently pick up the gemstone properly. Bring the tweezers up to position their tips just in front of your loupe, while your hand's palm faces you. At the same time, use your loupe-hand's ring and middle fingers to steady the tweezers in position by grasping them. This way both your loupe and tweezers will only have minimal shaking while you work.

Don't forget that its best to open both eyes while using the loupe, even if only one eye is being used to work. This actually helps alleviate strain. Practice makes perfect.

One noticeable characteristic of moissanite is its high level of dispersion. This allows it to showcase more "fire" or the spectral flashes of color you would see when rocking and tilting the stone under light. moissanite possesses a dispersion rate of 0.104, compared to diamond's lesser dispersion rate of 0.044. We can see through these numbers alone that moissanite's fire would most likely show up stronger than an equivalent quality of diamond. Now, to some this is a good thing, but there are also many jewelry lovers who describe moissanite's fire to have a "disco ball" effect, which might mean that its fiery appearance is too flashy for their taste. Personal preference has a major hand in the present moissanite demand on the market.

Moissanite is a Diamond Simulant / Imitation. It is Very Different from Natural OR Man-Made Diamond, Because it Possesses an Entirely Different Chemical Structure and Composition.

The stone's refractive index is also higher than diamond's, being at 2.65 to 2.69. Moissanite is actually a doubly refractive stone, unlike diamond or Cubic Zirconia. This means that once light enters its interior, it bends and changes direction slightly.


Moissanite can sometimes show "doubling", especially when viewed under a microscope. This can be observed by looking through the stone in magnification, and staring at either the back-facets or inclusions. Be careful though when testing this way, as the stone will have certain directions that will not showcase the doubling effect. This would be called an optic axis direction, and all doubly refractive gems (anisotropic gemstones) have at least one, depending on their crystal symmetry.

Hardness is another trait that moissanite scores well in. It belongs to the rate of 9.25 on the Moh's scale, which is even higher than ruby or sapphire. Diamond still reigns as the hardest mineral though at a Moh's rate of 10.

Virtually all moissanite you would see in the jewelry trade is man-made. The natural counterpart was discovered by a man named Henry Moissan back in 1893. These crystals are usually quite small and incredibly rare, so their usage in the jewelry trade would not merit much following. The stone's brilliance and optical properties though, gave scientists the motive to create synthetic versions using a process called sublimation.

Despite moissanite's diamond-like qualities, many specimens also tend to look a little greenish or grayish, depending on the quality of their production. This is one of the more negative observations regarding moissanite as a diamond simulant, however the best batches of man-made moissanite do not possess such a degree of color overcast, and instead can look very much similar to traditional colorless diamonds.

Today, the industry often uses "moissanite testers" to scan for these gems, as the standard electronic diamond testers can miss them (due to moissanite's high thermal conductivity).

Buyers who are familiar with diamonds and the way that they are color-graded, may have noticed slight visual differences in some stones of similar letter grades. Many factors can influence how a diamond appears after it is set into metal by an experienced jeweller.

For one thing, a diamond that is set into a piece of yellow gold jewellery will appear to be of a higher (less color) grade than it actually is. This is because the stone is seen in stark comparison to the bright yellow of the metal next to it. Many people appreciate this when buying stones that range in the K,L and M colors.




Whiter stones like those that belong to the D,E, and F colors can also be set into yellow gold jewellery as well, although they might fare equally well when mounted against the cold whiteness of platinum metal. The other yellowish stones (K,L,M) may look even more yellow when set into platinum or white gold mounts, purely because of the nearby visual comparison between the stone's color and the metal's absence of it.

Diamond Color Can be Sometimes Seem Affected by Factors Outside of its Color-Causing Trace Elements. The Presence of Fluorescence and the Chosen Jewelry Metal Type Can Also Change How We Evaluate a Stone's Color, Especially at First Glance.

Metals aren't the only thing that can make a diamond seem to possess more color than it actually has. Another property called fluorescence can also affect how we evaluate diamond color with our eyes. The presence of fluorescence in a stone means that it will also emit some amount of visible light when exposed to a source of radiation (including daylight). Most diamonds that possess fluorescence showcase it in a bluish tinge, which can sometimes make yellowish stones look less yellow, but can also allow whiter stones to look as if they possess a greater amount of color.



While fluorescence can make some stones look less colored, and others more colored, the general majority seems to side more with the absence of fluorescence as a better trait in diamonds today. Dealers may sometimes give a percentage discount for stones that have very strong fluorescence, and likewise put pricing priorities on those with a total absence of it.

The percentage can vary, we've seen many that range from about 3 to 6% off of industry price sheets (without yet factoring in dealer discount), but it's different from a case to case basis.

Many people also prefer the colored glow that fluorescence provides. Some diamonds with a very strong bluish fluorescence can have a slight ethereal feel to their appeal.

Not as much people are familiar with red spinel, but almost the entire world knows about the majesty of ruby. Both of these gemstones can come in a brilliant scarlet red, reaching vivid saturation levels on a pure earth-mined and untreated condition. Of course, those would be the top qualities of these gem varieties, and thus would command a hefty price in the industry.

To those who have seen the rarer fine qualities of red spinel, you must already be familiar with its likeness to ruby. The general trade also prizes spinel for its brilliant colors and fine luster. Its beauty is the favorite of many gemstone connoisseurs around the globe- and up until the 19th century, a vast majority of the general public actually believed this red gemstone to be ruby itself.

The advent of gemology and a better understanding of crystals gave way to the separation between these two gem varieties (which also belong to different species). Here, we will take a quick look at some of their differences.

First of all, rubies are a variety of corundum. This gem species belongs to the trigonal crystal system, is doubly refractive and will show "doubling" under strong enough magnification.

Spinel is a another gem species altogether, which belongs to the cubic crystal system. It is singly refractive, and therefore will never show any kind of "doubling" under magnification.

Doubling refers to the visual "duplication" of back facets or inclusions when you look through the gemstone's interior, provided you are not looking down an optic axis direction.

A polariscope can help you separate ruby from red spinel simply by observing if your red stone "blinks" or not as you turn it full circle under crossed polars. Ruby will do this because it is an anisotropic stone (DR), while spinel will not.

Ruby's hardness as the mineral species corundum is also rated at a 9 on the Moh's scale, while spinel ranks at an 8. Both gems are very hard with optimum durability traits.

When mining for them, rubies are most commonly found as hexagonal tablet shapes, while spinels could resemble partial or whole octahedral shapes.




Their specific gravities are also different, with spinel ranging at 3.58 to 3.61 and ruby at 3.9 to 4.1.
Some people are able to heft this difference by bouncing gemstones on their palms, but the more accurate way to determine SG would be using a scale with a hydrostatic attachment. You could also use SG heavy liquids at your preference.

Natural, Untreated Rubies Will Always Command Higher Prices Compared to Spinels of Equivalent Color Intensity and Overall Quality.

Separating ruby and spinel can also be supported by using a refractometer. Spinel has an RI value of 1.719, and shows a singular value (therefore there is no birefringence observation). Ruby on the other hand, shows RI values of around 1.762 to 1.770. This simply means that if you view the refractometer's scale while turning a polarizing filter in front of the viewer, you will see that ruby's RI value will change upon a 90 degree rotation. This value will first be around 1.762, then change to 1.770 upon the turn.

Both red gemstones are extremely remarkable, and can show us specimens of undeniable beauty and earthly rarity. Many people will agree that while they can often look very similar, an untreated ruby will usually have a much higher price compared to a red spinel of its equivalent quality. This is true especially in the finest hierarchies of their color and clarity grades levels.