18 - 20 mm Opal Gemstones

18 - 20 mm Opal Gems

Gemstone Information

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Over 19 Years in the Gemstone Business!

Thank you for trusting us with your purchase!

Overall Rating -> 10

i made an order in 2007 and was very pleased; it made into a lovely ring. i found a large citrine locally, and now needed some accent stones.

Posted By Morgana zanos in March, 2023

Source: Bizrate

Overall Rating -> 8

Takes forever to be finished. Pain in the rear

Posted By Nothanks in September, 2023

Source: Bizrate

Overall Rating -> 10

I recently bought some stones for Christmas gifts for my family from GemSelect and was thrilled at the speed they arrived to me. The descriptions were accurate and could be verified by myself upon receiving the stones, though the only issue i had was finding exact stones i wanted. The sorting system is fanastically detailed, but often seems to trim more results than expected when i was selecting things to look by. They arrived safely and all together, as described per my purchase order and i could not be more satisfied. There aren't many that are looking to buy loose stones like this, but it really gets the job done.

Posted By Lev in December, 2022

Source: Bizrate

Overall Rating -> 10

I’ve enjoyed purchasing stones from this site. It’s convenient and fairly priced.

Posted By Chico in May, 2023

Source: Bizrate

Overall Rating -> 10

blessed be the lord blessed be the saved blessed be the work blessed be the traveled i write down my good times in these stones and when times are gray i can still se the sunny days refract in these stones

Posted By Kickbass.2 in May, 2023

Source: Bizrate

Overall Rating -> 10

Everything was perfect, the stone was gorgeous, and delivery was on time. I cannot add anything else.

Posted By DesertDweller in March, 2023

Source: Bizrate

Overall Rating -> 10

Purchasing from Gem Select was a pleasant and easy experience. The photos of the stones I was interested in were an accurate depiction of the stones I received. Ordering was easy and the items arrived within a week. Over all it was a very positive experience.

Posted By Dee in September, 2023

Source: Bizrate

Overall Rating -> 10

GemSelect has the Best gems. Clear photos and detailed description helps me make the best choice. I have Never been disappointed by thier quality items.

Posted By Rock Hound in July, 2023

Source: Bizrate

Overall Rating -> 10

Fantastic dealer for quality gemstones. Website is easy to navigate, selection is superb, delivery of purchases is prompt. Easy to select incorrect payment options, however.

Posted By David W in May, 2023

Source: Bizrate

Overall Rating -> 10

I'd like to recommend GemSelect, great items, quality, customer service & fast deliveries.

Posted By Tadeo in December, 2022

Source: Bizrate

Overall Rating -> 10

I was very happy with the simplicity and prices of gemselect.com. the sites filters and navigation style made it simple to find exactly what I was looking for. I will definitely be buying from gemselect ago. Compared to other online stone sellers, the prices and availability of gemselect was amazing.

Posted By Jl1996 in November, 2022

Source: Bizrate

Overall Rating -> 10

I particularly like information about product provided with purchase.

Posted By Dick in May, 2023

Source: Bizrate

Overall Rating -> 10

Beautiful selection of gems! Surprised and happy that I was able find a gem in my price range.

Posted By Garnet T in January, 2023

Source: Bizrate

Overall Rating -> 8

Great selection, good prices and beautiful, simple user interface.

Posted By Swaggermuffinz in October, 2022

Source: Bizrate

Overall Rating -> 8

i was hoping to find more stones smaller than 3mm

Posted By Jerdo in December, 2022

Source: Bizrate

Selected Gemstones

Gemstones A-Z

Buy 18 - 20 mm Opal Gems

18.23 ct Green Opal, 19.9 x 17.4 mm Oval Cut From Brazil

4.71 ct Pear Cut Opal, 18.4 x 11.7 mm From Australia

3.48 ct Pear Cut Opal, 18.4 x 9.8 mm From Ethiopia

13.64 ct Oval Opal, 18.5 x 15 mm From Ethiopia

8.62 ct Green Opal, 20 x 14.5 mm Pear Cut From Brazil

8.21 ct Green Opal, 18.5 x 12.5 mm Oval Cut From Brazil

16.51 ct Green Opal, 19.6 x 16.1 mm Oval Cut From Brazil

18.9 ct Green Opal, 18.9 x 15.8 mm Oval Cut From Brazil

10.37 ct Green Opal, 18.2 x 13.5 mm Oval Cut From Brazil

9.93 ct Green Opal, 19.3 x 13.3 mm Oval Cut From Brazil

25.42 ct Green Opal, 19.8 x 15.7 mm Oval Cut From Brazil

14.52 ct Green Opal, 18.9 x 14.8 mm Oval Cut From Brazil

13 ct Pear Opal, 19.4 x 13.6 mm From Brazil

9.66 ct Oval Opal, 18.4 x 13.5 mm From Ethiopia

24.39 ct Green Opal, 19.2 x 17.8 mm Oval Cut From Brazil

7.29 ct Green Opal, 18.4 x 12.2 mm Oval Cut From Brazil

16.5 ct Green Opal, 18.6 x 13.4 mm Oval Cut From Brazil

15.66 ct Green Opal, 19.6 x 15.1 mm Oval Cut From Brazil

9.96 ct Green Opal, 18.8 x 13.8 mm Oval Cut From Brazil

12.46 ct Green Opal, 18 x 13.7 mm Oval Cut From Brazil

11.93 ct Green Opal, 19.1 x 14.9 mm Oval Cut From Brazil

7.07 ct Pear Opal, 19.1 x 13.5 mm From Australia

5.82 ct Pear Opal, 19.2 x 11.4 mm From Australia

12.06 ct Trillion Opal, 18 x 17.2 mm From Ethiopia

15.72 ct Oval Opal, 19.5 x 17.1 mm From Ethiopia

18 - 20 mm Opal Gems

Gemstone Information