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Natural Star Gemstones

Discover rare star gemstones displaying the fascinating star effect known as asterism, perfect for collectors and unique jewelry designs.

Star Gemstones Weight
Star Gemstones Size
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Black Star Gemstones
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Orange Star Gemstones
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Purple Star Gemstones
Red Star Gemstones
Turquoise
Violet
White
Yellow Star Gemstones
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13.31ct Mahogany Red Star Garnet, Oval, Opaque

14 x 12 mm (calibrated)

$ 15.82

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2.08ct Black Star Diopside, Oval, Opaque

8 x 6 mm (calibrated)

$ 12.48

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18.41ct Reddish Purple Star Ruby, Oval, Opaque

15.4 x 13.7 mm

$ 291.61

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1.56ct Black Star Diopside, Oval, Opaque

8 x 6 mm (calibrated)

$ 9.36

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4.25ctw Dark Blue Star Sapphire, Oval, Opaque

7 x 5.2 mm

$ 93.50

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10.57ct Dark Red Star Garnet, Oval, Opaque

12.5 x 9.7 mm

$ 12.55

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15.64ct Mahogany Red Star Garnet, Oval, Opaque

12.9 x 11.4 mm

$ 18.58

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4.46ctw Deep Navy Blue Star Sapphire, Oval, Opaque

7.1 x 5.3 mm

$ 117.74

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14.18ct Reddish Purple Star Ruby, Oval, Opaque

16 x 12 mm (calibrated)

$ 224.62

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16.58ct Raspberry Red Star Ruby, Oval, Opaque

14.3 x 13 mm

$ 238.75

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6.83ct Black Star Sapphire, Oval, Opaque

11.7 x 9.4 mm

$ 163.92

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24.09ct Mahogany Red Star Garnet, Oval, Opaque

16 x 13 mm

$ 28.62

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11.74ct Black Star Diopside, Round, Opaque

12 mm (calibrated)

$ 70.44

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17.40ct Grayish Magenta Star Ruby, Oval, Opaque

15 x 12.8 mm

$ 275.62

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4.92ct Black Star Diopside, Oval, Opaque

11 x 9 mm (calibrated)

$ 29.52

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4.81ct Black Star Diopside, Oval, Opaque

11 x 9 mm (calibrated)

$ 24.05

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4.89ct Black Star Sapphire, Oval, Opaque

11 x 9 mm (calibrated)

$ 117.36

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4.60ct Deep Crimson Star Ruby, Oval, Opaque

9 x 7.9 mm

$ 88.32

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4.61ctw Deep Blue Star Sapphire, Oval, Opaque

7.1 x 5.2 mm

$ 121.70

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8.80ct Very Light Grey Star Sapphire, Round, Opaque

11 mm (calibrated)

$ 369.60

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12.41ct Mahogany Red Star Garnet, Oval, Opaque

15.6 x 12.6 mm

$ 14.75

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3.34ctw Dark Blue Star Sapphire, Oval, Opaque

7 x 5 mm (calibrated)

$ 79.36

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10.93ct Deep Wine Red Star Ruby, Oval, Opaque

12.9 x 10.6 mm

$ 131.16

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9.82ct Black Star Diopside, Round, Opaque

12 mm (calibrated)

$ 58.92

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Why Buy Star Gemstones from GemSelect?

Natural Star Gemstones

Our natural star gemstones display the rare optical phenomenon known as asterism, where a star-shaped reflection appears across the gem’s surface. These unique stones are prized by collectors and jewelers for their striking appearance and rarity.

Star Gemstones Online

Buy star gemstones online at GemSelect with confidence. Our collection includes star sapphire, star ruby, and other rare gems with visible star effects, all available as loose stones ready for custom jewelry.

Loose Star Gemstones with Asterism

The Unique Star Effect (Asterism)

The star seen in these gemstones is caused by tiny needle-like inclusions that reflect light in a star-shaped pattern. This optical phenomenon, called asterism, becomes visible when the gemstone is cut as a smooth cabochon.

Star Sapphire Gemstones

Star sapphire is the most famous star gemstone, often displaying a clear six-rayed star across its surface. These gems are durable and popular for rings, pendants, and collector pieces.

Star Ruby Gemstones

Star rubies are rare and highly valued. When illuminated, they reveal a sharp star pattern over their deep red body color, making them one of the most sought-after asterism gemstones.

Cabochon Cut Star Stones

Star gemstones are typically cut as cabochons rather than faceted stones. The smooth, domed surface allows the star effect to appear clearly when the gem is viewed under direct light.

Loose Star Gemstones for Jewelry

Loose star gemstones are perfect for custom jewelry designs. Their distinctive optical effect makes them ideal for rings, pendants, and statement pieces that stand out from traditional faceted gems.

Collectible Star Gemstones

Many collectors seek star gemstones due to their rarity and unusual appearance. High-quality stones with centered and well-defined stars are especially desirable among gem enthusiasts.

Learn more about the properties and fascinating optical effects of gemstones on our Gemstone Optical Effects Guide.

FAQs

What are star gemstones?

Star gemstones are gems that display a star-shaped reflection on their surface. This optical phenomenon is called asterism and is most commonly seen in star sapphire and star ruby.

What causes the star effect in gemstones?

The star effect is caused by microscopic needle-like inclusions inside the gem that reflect light in intersecting lines, creating a visible star pattern when viewed under direct light.

Which gemstones show a star effect?

The most well-known star gemstones are star sapphire and star ruby, but asterism can also appear in gems like star garnet, star diopside, and occasionally in quartz.

Why are star gemstones cut as cabochons?

The cabochon cut allows the star pattern to appear clearly on the gem’s surface. Faceting would disrupt the optical effect and prevent the star from forming.

How can you see the star in a gemstone?

The star becomes visible when light hits the surface of the gemstone. Rotating the stone under a light source will make the star move across the surface.

GemSelect Certified Store Reviews

GemSelect: Over 22 Years in the Gemstone Business! Thank you for trusting us with your purchase!

Overall Rating -> 8 star ratings

I visited several online loose stone shops trying to find rare stones. I finally found one that I've been looking for here, and very satisfied. Looking forward to receive the item in 3 weeks.

Posted By Atsu in December, 2025
Source: Bizrate

Overall Rating -> 9 star ratings

It was great!

Posted By Annie in September, 2025
Source: Bizrate

Overall Rating -> 10 star ratings

Love how easy the site is to use. Really love that the pictures are of actual product.

Posted By LeAnn in January, 2026
Source: Bizrate

Overall Rating -> 10 star ratings

Love the precise descriptions and calibrations of hte loose gemstones. Would like to have seen more variety in the size gem I was looking for.

Posted By RenoRose in January, 2026
Source: Bizrate

Overall Rating -> 10 star ratings

The website has a good selection, the interface is very intuitive.

Posted By PhoenixFeatherJewelry in January, 2026
Source: Bizrate

Overall Rating -> 9 star ratings

Always a good quality stone. Priced fairly and shipped promptly. Answers emails quickly

Posted By Ron T in November, 2025
Source: Bizrate
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