Spinel Vs. Corundum


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Gem-related Field

Today's Question:
How Can You Tell The Difference Between Spinel And Corundum?
The majority of blue spinel has a significant grey mask and hence lacks the blue hue of a fine sapphire. This, combined with the fact that spinel is significantly less popular than sapphire, results in a lower overall price. However, the benefits of spinel are its rarity of treatment (it is occasionally heated or fracture filled), and its exceptional luster, fire, and durability. It has a high refractive index. Due to these factors, some people ignore the greyer colour, particularly in a well-cut spinel.

Additionally, they lack the zoning that sapphires exhibit. This has resulted in extremely high prices for unheated sapphires - especially since the emergence of the Kate/Diana ring.
Usually, fancy sapphires have more vibrant hues, as profoundly saturated spinels are scarce. Spinels are rarely treated, and while their color is frequently altered by grey tones, collectors prefer the gemstone's original state.
Spinel's crystal structure contains around 17% magnesium, making it slightly softer than sapphire. Although its optical qualities are extremely similar to sapphire, it has an isometric (cubic) crystal structure, which results in spinels that are colorless in all directions, whereas sapphire is always dichroic (varying hue along the 'C' axis).

How Come Spinels Are Less Expensive Than Sapphires?
Spinels are less expensive than sapphire mostly due to their lack of public awareness. This is also likely given the ease and low cost by which spinel may be created synthetically. It has been used in that form for maybe a century, causing the general public (and most jewelers who were not gemologically savvy) to view spinel as a cheap material for low-quality jewelry. That has changed greatly over the last two decades, with fine spinel now commanding prices comparable to sapphire.

We could never express enough how essential it is to get stones from reliable gemstone sellers. If you are unsure about the seller, always search for blue spinels with visible natural inclusions or ones that are not overly saturated in color.
While both spinels and sapphires have high refractive indices, spinels are singularly refractive, similar to diamonds, and are valued for their striking shine.

Spinel: August Birthstone
The American Gem Trade Association and the Jewelers of America designated spinel as the new August birthstone in July 2016. Previously, peridot was the August birthstone. Spinel and peridot will now have the same classification. This event, along with the ongoing marketing of monthly birthstones, will increase awareness of spinel, which comes in a range of colors. Customers will now have additional color options when it comes to the yellow-green hue of peridot.

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Benjamin Poudevigne
Social Media Manager at GemMatrix
With over ten years of marketing experience, I finally decided to settle down in Bangkok to work in an area that I have always been interested in: the gemstones industry. I'm still learning how the market works on a daily basis, and I enjoy sharing my experience with those who are interested in learning more about gems in general.