Top 10 Gemstones with Desired Inclusions
Inclusions are elements from other minerals or objects (foreign matter/material, or irregularities in the crystal lattice).In general, inclusions are considered flaws that are unwanted in gemstones because they can often cause cracking, chipping, breaking, and other structural weaknesses.
However, in rare cases, inclusions are highly desirable. This list focuses on valuable gemstone inclusions - those so-called "defects" that enhance a gem's uniqueness and often make it more interesting and more expensive than varieties without inclusions.

Star Rubies are a rare variety of ruby that is highly prized. The "star effect" is due to inclusions of rutile needles, also known as "silk." Rutile is a crystal of titanium dioxide that occurs in several gems and is perhaps the most desired inclusion.
Only 3 out of 100 rough rubies will have stars. However, out of these three:
1. One will have a good star but poor color.
2. One will have a poor star but good color.
3. Only one out of 100 will have both a good star and a good color!
Most star rubies are pinkish-red, purplish-red, or purplish-brown. A red ruby with a perfect star is very rare and costly. Usually, pink star rubies have the best stars.

How does this green gem get a beautiful black and green 6-point radial pattern? Actually, only the green sections are emerald crystals, while the black sections are dark carbon impurities that entered the gemstone structure during its formation. They formed a 6-point pattern because emeralds have a hexagonal crystal structure (6-sided crystals), and the dark impurities filled in at the crystal junctions.
However, carbon hardness varies, making Trapiche Emerald susceptible to cracking, chipping, and breaking. The carbon acts like coal between the emerald crystals, and its hardness can vary from graphite to diamond.

Star Sapphire's "star effect" is due to the same inclusions described in Star Ruby and Cat's Eye - rutile silk. Only 3 out of 100 rough sapphires will have stars (for more details, read my item description for Star Ruby above. Everything is the same). Star sapphires can occur in all colors except red because the red variety of corundum is already called ruby.
This might be cooler than the star ruby!

The Cat's Eye effect is produced by needle-like rutile inclusions or microscopic tube-like cavities, visible as a single ray of light passing across the crystal. Chrysoberyl is the third hardest gemstone at 8.5 on the hardness scale, after diamond at 10 and corundum at 9 (ruby and sapphire). It's harder than topaz (8).
Chrysoberyl is a great gem, and Cat's Eye Chrysoberyl is its most prized variety, mainly for the inclusions.


Rutile inclusions (rutile needles or silk) form lovely patterns inside quartz. These inclusions mostly look golden, but they can also appear silver, copper red, or deep black. Rutile needles can be sparse or dense, distributed randomly or in bundles, and can sometimes be arranged in star-like formations. Rutilated quartz is valued for the quality and beauty of these inclusions. Without the rutile inclusions, it's just plain quartz.
Rutilated quartz is also quite hard, with a Mohs hardness of 7 (for comparison, amethyst is also at 7).


Unlike most inclusions, amber inclusions are organic. Amber may contain organic matter that was trapped in the gem about 50 million years ago, mostly insects and plant material. Amber is well-known for these inclusions.
Amber is the fossilized, hardened resin of ancient trees.

Lapis Lazuli is usually royal blue, but pyrite inclusions give it its golden shimmer. By the way, Lapis Lazuli is actually a rock used as a semi-precious gemstone. The reason? Its intense color and the golden pyrite inclusions. It is one of only a few rocks used in jewelry making.

(Also known as Dendritic Opal)
Moss Opal carries dendritic inclusions that form dark-green, moss-like patterns. Without the dendritic inclusions, it's just a common opal of no particular interest.
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It contains incredibly beautiful dumortierite inclusions.


Tiger's Eye is a gem from the quartz group with a silky luster and many stripes. This occurs when quartz crystals include altered amphibole fibers that have mostly turned into limonite. Inclusions make this quartz interesting.

Jasper contains up to 20% foreign material, which explains its multicolored, striped, spotted, or flamed appearance.

Even though its hardness is a bit low, it still looks beautiful!
Inclusions in Moonstone make it glow like the moon. Its Mohs scale hardness is 6 - 6.5, which is relatively low.