Big lab gems
Lab-grown gems are real gem minerals, so the thing that makes a mined ruby, sapphire or emerald priceless, size, becomes cheap. A lab ruby of 10 carats, a 30x20 mm oval, or a ruby ring with a 5 carat centre are all ordinary Amazon purchases. The rule is honest labelling: buy stones called lab-created, created or synthetic, and pick the size in millimetres.
The biggest lab gems you can buy on Amazon right now
Real lab-grown stones only, biggest first. Photos are the listings' own.
Amazon prices as of . Prices and availability are accurate as of that date and time and are subject to change; the price shown on Amazon at the time of purchase applies.
Lab ruby 52.5 ct Gryrigns round brilliant, 25 mm, 52.5 ct about $60 A round lab ruby an inch across: the biggest faceted lab ruby we trust on Amazon. See it on Amazon → 
Lab ruby 48 ct Gryrigns oval, 30 x 20 mm, 48.3 ct about $55 A huge oval: 30 by 20 millimetres of real corundum. See it on Amazon → 
Lab ruby 30 ct Gryrigns emerald cut, 20 x 15 mm, 29.83 ct about $35 The classic emerald cut at almost 30 carats. See it on Amazon → 
Lab ruby 19 to 23 ct Instagem Swiss-grown ruby, emerald cut, 18 x 13 mm about $130 Cut from Swiss-made rough by a dealer that grades every stone. See it on Amazon → 
Lab sapphire 29 ct Gryrigns royal blue, emerald cut, 20 x 15 mm, 28.96 ct about $75 The biggest blue we trust. See it on Amazon → 
Lab sapphire 8.6 ct Gryrigns cornflower blue, radiant cut, 14 x 10 mm, 8.61 ct about $35 The lighter, brighter blue of Ceylon sapphire. See it on Amazon → 
Lab emerald 11 to 15 ct Instagem emerald cut, 18 x 13 mm about $1,050 Real lab emerald costs real money: months to grow. See it on Amazon → 
Lab emerald 10 to 11.5 ct Instagem oval, 18 x 13 mm about $660 The biggest oval lab emerald we trust. See it on Amazon → 
Lab diamond 10.5 ct IGI-graded radiant cut, 10.5 ct, D to E, VVS to VS about $4,400 The biggest size of the biggest lab diamond listing we found. Sold as total weight: confirm it is one stone. A new listing: look up the IGI number before you pay. See it on Amazon → 
Lab diamond 9 ct IGI-graded round brilliant, 9 ct, D to E, VVS to VS about $4,050 The biggest round lab diamond we found. See it on Amazon → 
Moissanite 10 ct Pmfxinyao round moissanite, 10 ct, D colour, with GRA card about $160 Lab-grown silicon carbide, harder than any gem but diamond. See it on Amazon → 
Lab sapphire rough 150 ct Gryrigns blue sapphire boule with its domed top, 150 ct about $65 Uncut, straight from the flame. Near black in a thick piece; thin cut stones show the royal blue. See it on Amazon → New: the lab gem catalog, all 470 checked listings with filters for cut, size and type. And Lab gems worth buying, the checked list: a 30 carat lab ruby for tens of dollars, honest lab emerald, rough, star stones, meteorites, and a weight checker that tells from glass.
Big lab rubies
Questions first
- Are lab rubies real rubies? Are lab-created rubies real rubies? What a lab ruby is made of, how it is grown, how it differs from a mined ruby, and what it should be called.
- How big is a 5 carat ruby? Ruby size chart: millimetres to carats for round rubies from 6 mm to 18 mm, why a ruby weighs more than a diamond of the same size, and how big a 5 carat ruby is.
- Is a cheap "natural certified" ruby on Amazon real? Amazon listings offer “natural, unheated, certified” rubies of 5 carats or more for the price of a meal. What those stones may really be, what US rules say the label must say, and the 10x loupe check.
Big lab sapphires and emeralds
The same logic works for blue sapphire (corundum, like ruby) and emerald (). Searches narrowed to honestly labelled large stones:
Frequently Asked Questions
Why buy big lab gems?
A lab ruby or sapphire is the real mineral (corundum), and a lab emerald is real beryl, grown instead of mined. That turns sizes that would be museum pieces as mined stones into affordable ones: a 10 carat lab ruby costs about what a meal out does.
Do big lab gems have resale value?
Very little. Buy them to enjoy, collect and wear; the value of a set piece is mostly its metal.
What should the listing say?
Lab-created, lab-grown, created or synthetic, followed by the gem name. "Simulated" means an imitation such as glass, and "natural" at a lab-gem price is a red flag.
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