X
Gemstone Search
90,000+ Happy Customers
20+ Years In Business
Call Us Mon–Fri 8am–5pm

Your Details

Please fill in your email address

Please fill in a password

Forgot your password?

Buy 12 mm Round Calibrated Gemstones from GemSelect

Round Shape 12 mm Gems Weight
Round Shape 12 mm Gems Size
Round Shape 12 mm Gems Clarity
Round Shape 12 mm Gems Price

Size Explained

Choose Size or Size Range
For Example: 6-7
For Example: 8-9
Bi-color
Black Round Shape 12 mm Gems
Blue Round Shape 12 mm Gems
Brown Round Shape 12 mm Gems
Golden
Gray Round Shape 12 mm Gems
Green Round Shape 12 mm Gems
Multicolor Round Shape 12 mm Gems
Orange Round Shape 12 mm Gems
Pink Round Shape 12 mm Gems
Purple
Red Round Shape 12 mm Gems
Turquoise Round Shape 12 mm Gems
Violet Round Shape 12 mm Gems
White Round Shape 12 mm Gems
Yellow Round Shape 12 mm Gems
Single
Pairs
Lots
Faceted
Cabochons
Clear All

8.40ct White Quartz Cat'S Eye, Round, Transparent

12 mm (calibrated)

$ 36.81

View Gem

9.33ct Multicolor Agate, Round, Opaque

12 mm (calibrated)

$ 13.16

View Gem

8.74ctw Multicolor Labradorite, Round, Translucent

12 mm (calibrated)

$ 19.16

View Gem

10.10ct Multicolor Agate, Round, Opaque

12 mm (calibrated)

$ 9.56

View Gem

8.50ct White Quartz Cat'S Eye, Round, Transparent

12 mm (calibrated)

$ 30.17

View Gem

14.23ctw Black Spinel, Round, Opaque

12 mm (calibrated)

$ 46.77

View Gem

6.75ct Brown Tiger'S Eye, Round, Opaque

12 mm (calibrated)

$ 8.75

View Gem

7.68ct Green Maw-Sit-Sit, Round, Opaque

12 mm (calibrated)

$ 25.24

View Gem

12.39ct Gray Pearl, Sphere / Ball, Opaque

12 mm (calibrated)

$ 203.62

View Gem

12.60ct Green Maw-Sit-Sit, Round, Opaque

12 mm (calibrated)

$ 41.42

View Gem

8.06ct Black Star Diopside, Round, Opaque

12 mm (calibrated)

$ 40.14

View Gem

5.78ct Brown Smoky Quartz, Round, VVS

12 mm (calibrated)

$ 11.35

View Gem

5.47ct Yellow Quartz, Round, VVS

12 mm (calibrated)

$ 29.97

View Gem

5.48ct Multicolor Mystic Quartz, Round, VVS-VS

12 mm (calibrated)

$ 16.38

View Gem

6.38ct Brown Smoky Quartz, Round, VVS

12 mm (calibrated)

$ 7.62

View Gem

10.73ct Red Star Garnet, Round, Opaque

12 mm (calibrated)

$ 10.57

View Gem

6.28ct Yellow Citrine, Round, VVS

12 mm (calibrated)

$ 48.16

View Gem

10.11ct Black Star Diopside, Round, Opaque

12 mm (calibrated)

$ 50.35

View Gem

6.17ct Yellow Quartz, Round, VVS

12 mm (calibrated)

$ 24.47

View Gem

6.16ct Brown Smoky Quartz, Round, Transparent

12 mm (calibrated)

$ 25.85

View Gem

13.47ctw Black Spinel, Round, Opaque

12 mm (calibrated)

$ 44.27

View Gem

5.35ct Yellow Quartz, Round, VVS

12 mm (calibrated)

$ 29.32

View Gem

15.03ctw Black Spinel, Round, Opaque

12 mm (calibrated)

$ 49.40

View Gem

5.26ct Yellow Quartz, Round, VVS

12 mm (calibrated)

$ 21.15

View Gem

Why Buy Round Shape 12 Mm Gems from GemSelect?

GemSelect Certified Store Reviews

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

Overall Rating -> 9 star ratings

I did not realize these stones were of jewelry quality. They are really beautiful, just not what I was expecting which was more of a natural stone.

Posted By Jewelry Quality Stones in July, 2025
Source: Bizrate

Overall Rating -> 8 star ratings

Site worked well and helped me find a rock that matched what I was looking for. Well within budget and I trust it will show up, so that's definitely positive. Not much else to it. Satisfied.

Posted By Big Ricky in May, 2026
Source: Bizrate

Overall Rating -> 10 star ratings

I was looking for high-quality amethyst on this site, and I was able to compare size, color, and weight in detail before making a purchase.

Posted By Atsuhisa in January, 2026
Source: Bizrate

Overall Rating -> 10 star ratings

hassle free experience.

Posted By Jhidron in October, 2025
Source: Bizrate

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 -> 10 star ratings

overall great

Posted By SR in April, 2026
Source: Bizrate
Enlarged Gemstone Image