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Cut Gemstones

Step, brilliant, mixed, fancy and cabochon cuts worked from Brazilian topaz, Russian beryl, Ethiopian opal and Persian turquoise.

Buy Cut Gemstones Loose, Priced by Carat Weight, Cut Style and Setting Readiness

A cut gemstone is a rough crystal that a lapidary has faceted or domed to deliberate angles so light entering the table returns to the eye instead of leaking away through the pavilion. Buy a gem loose rather than already mounted and you judge carat weight, cut style, girdle thickness and colour on their own terms before a jeweller commits the stone to metal. Astro Gallery of Gems weighs, measures in millimetres and photographs each of the 35 loose stones catalogued here, from an 8.3 carat Persian turquoise cabochon to an 1185.5 carat Brazilian blue topaz worked as an emerald step cut.

Shop the Five Cut Families Worked on This Page

Cut style governs how a gemstone behaves in daylight and what a setter can safely do with it afterwards. Astro Gallery sorts the loose material here into five working families, and every listing names the family that the gem belongs to.

Cut familyWhat it does to the stone and who buys it
Step cuts: emerald and baguetteLong parallel facets run in tiers around a rectangular table, as on the 1185.5 carat Brazilian blue topaz and the 86 carat rutilated quartz baguette. Designers reach for a step cut when clarity is the selling point, because this outline hides nothing.
Round brilliantFifty eight facets meet at calculated crown and pavilion angles, as on the 307.5 carat South African amethyst. This family returns the sharpest scintillation on the page and drops straight into a solitaire head or a claw mount.
Mixed ovalA brilliant crown sits above a step cut pavilion, the treatment given to the 166 carat Russian heliodor and the 309.5 carat smoky quartz. Buyers choose it when saturated body colour matters as much as sparkle.
Fancy outlines: trillion, pear and teardropThe 227.5 carat Madeira citrine teardrop, the 36.5 carat citrine trillion and the 9 carat tourmaline pear carry the silhouettes that pendants and drop earrings need.
CabochonsA domed unfaceted top over a flat back, used on the 28.5 carat Ethiopian opal and the Persian turquoise cabochons. Lapidaries reserve this treatment for play of colour, matrix patterning and any material softer than quartz.

Order a Loose Stone at the Rate Showing Against It Today

Each row below is a single gem, weighed on a calibrated scale and photographed loose on a neutral card before it went online. Astro Gallery prices every stone against its own carat weight, cut quality and colour saturation, and a gem that sells drops out of this table.

PieceDetailPrice
1185.5ct. Blue Topaz Emerald Cut Gemstone from Brazil See listing $ 41,500.00
166 Carat Heliodor Oval Cut Gemstone from Russia See listing $ 4,650.00
307.5 Carat Amethyst Round Brilliant Cut Gemstone from South Africa See listing $ 7,700.00
227.5 Carat Citrine Teardrop Cut Gemstone from Brazil See listing $ 11,500.00
313.5 Carat Amethyst Oval Cut Gemstone from Brazil See listing $ 12,500.00
Opal Gemstone Cabochon (28.5ct) 28.5ct $ 2,900.00
Every loose stone here is one of oneAstro Gallery photographs the exact gem you receive, states its carat weight and millimetre dimensions, and holds the figure on the listing through secure checkout.
Buy from all 35 loose stones Request a daylight video

Where the Rough Was Mined and What Origin Changes

Origin sets the colour range a species can reach, the sizes that reach a cutting wheel and the treatments the trade expects. Astro Gallery buys rough and finished singles at the shows and direct from cutters, and names the source on the listing wherever the seller can substantiate it.

Minas Gerais, BrazilBrazilian pegmatite and vein quartz supply the amethyst, Madeira citrine, smoky quartz and rutilated quartz here, all silicon dioxide at Mohs 7. That hardness lets a cutter take large clean weights, which is why the biggest faceted stones on this page are Brazilian.
Russian golden berylHeliodor is the golden variety of beryl, a beryllium aluminium silicate at Mohs 7.5 to 8 that resists scratching better than quartz. Russian material carries a honey tone rather than a lemon one, so it reads warm against yellow gold and cool against platinum.
Wollo, EthiopiaEthiopian opal is a hydrated silica at Mohs 5.5 to 6.5 whose play of colour comes from ordered silica spheres diffracting light. This material is hydrophane, meaning it takes up water and can shift transparency, so a jeweller should set it in a protective bezel.
Neyshabur, KhorasanThe trade name Persian turquoise points at the Khorasan workings, and the mineral is a hydrated copper aluminium phosphate at Mohs 5 to 6. Softness and porosity explain why these two stones arrive as cabochons rather than faceted gems.

Calibrated Millimetre Sizes Against One of One Custom Cuts

Two very different buyers reach this page, and the millimetre reading on the listing tells you immediately which path a given gem belongs to.

Calibrated commercial sizesA calibrated stone is cut to a standard footprint such as 7 by 5 millimetres or 8 by 6 millimetres, so it drops into a ready made head or a stock semi mount without bench work. Jewellers who repeat a design order calibrated goods because the setting cost stays predictable and a replacement matches.
One of one custom cutsMost gems catalogued here are singles cut to whatever the rough allowed, which is why dimensions run to figures such as 45 by 35 by 70 millimetres on the blue topaz. A goldsmith fabricates the mount around the gem, and Astro Gallery supplies the measured millimetre readings a wax carver or CAD designer needs to begin.

Four Faults to Rule Out Before You Purchase a Loose Stone

Cutting shortcuts and undisclosed treatment account for most disappointment in loose goods, and all four show up in photographs taken against a plain background.

Windowing through the pavilionA window is the washed out patch in the middle of a gem cut too shallow, where light passes straight through instead of reflecting. Hold the listing photograph against printed text: a well angled pavilion hides the type, while a windowed stone lets you read it.
Girdle thickness and chippingA knife thin girdle chips during setting and a bulky one hides weight the buyer pays for without seeing. Astro Gallery photographs each gem in profile so the girdle line reads clearly before a setter ever touches the stone.
Extinction and facet symmetryExtinction is the dark zone that appears when facets meet at inconsistent angles and return no light. A symmetrical cut keeps its light and dark pattern ordered, while a rushed one blacks out across a whole quarter.
Treatment stated in plain wordsBlue topaz is normally irradiated and heated, most commercial citrine begins as heated amethyst, and turquoise is frequently stabilised with resin. Astro Gallery describes the Brazilian topaz and the Brazilian amethyst here as natural and untreated, and says so in the listing text rather than leaving you to assume it.

Terms Printed on a Loose Gemstone Listing

TableThe table is the large flat facet on top of a faceted gemstone, and its width relative to the outline governs how much light the stone gathers.
GirdleThe girdle is the narrow band around the widest part of a gem where crown meets pavilion, and it is the surface a claw or bezel grips.
WindowA window is the see through zone in the centre of a shallow stone, and it costs a gem both apparent colour and apparent brilliance.
ExtinctionExtinction describes the dark areas a gemstone shows when light entering the crown fails to reflect back, and heavy extinction indicates poor pavilion angles.
Mixed cutA mixed cut carries brilliant facets on the crown and step facets on the pavilion, a combination that holds body colour while still throwing light.
HydrophaneHydrophane describes porous opal that absorbs water and temporarily changes transparency, which is why Ethiopian opal should never be soaked or steam cleaned.

Carat Weight, Wearability and the Life a Stone Will Lead

Carat weight decides scale rather than diameter, since one carat equals 0.2 grams and a dense species reads smaller than a light one at equal weight. Stones under roughly 40 carats here, including the 9 carat tourmaline pear and the 21 carat ametrine, suit rings, pendants and earrings that get daily wear. The 227.5 carat citrine and the 313.5 carat amethyst belong on statement necklaces, in cased collections or in a display cabinet where their millimetre depth becomes the point. Collectors buy across species deliberately, assembling a run of cut styles or a run of localities, and a boxed loose gem makes a graduation, engagement or milestone birthday gift that the recipient later designs around.

Cleaning a Faceted Stone Before It Reaches the Bench

Hardness dictates the routine, so treat the softest material on the page as the rule. Turquoise at Mohs 5 to 6 and Ethiopian opal at Mohs 5.5 to 6.5 are porous, and both should be wiped with a dry lint free cloth and kept away from solvents, perfume and standing water. Never put opal or turquoise into an ultrasonic or a steam cleaner, because vibration and heat drive water through the structure and can craze the surface permanently. Quartz, topaz, tourmaline and beryl take warm water with a drop of plain soap and a soft brush, then a dry cloth before the gem goes back into its paper.

Ordering, Insured Transit and the Documents in the Box

Astro Gallery of Gems has traded loose goods since 1961, and the buying route is short. The figure on the listing is the figure charged, secure checkout settles through Shop Pay, PayPal, Apple Pay, Google Pay or a Visa, Mastercard, Discover and Diners Club card, and an itemised invoice naming the species, carat weight and millimetre dimensions travels with the parcel. Ask our team for a daylight video, a reading against a millimetre rule or a profile shot of the girdle before you commit, and we send those files the same working day.

Astro Gallery packs faceted goods in individual gem paper inside a rigid box so that no two stones touch in transit, then double boxes the carton. Every parcel leaves tracked and fully insured to the declared value, and we complete the customs paperwork before dispatch on export orders so a gem is not held at the border. Our published returns policy and the guarantee on our about us page govern what happens if a stone does not suit the design you had in mind.

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Check the stone against your setting firstSend the millimetre footprint your mount needs and we will name the loose gems on this page that fit it.
Shop the loose gemstones Email the gemstone desk

Before You Add a Loose Stone to the Cart

How much does a loose cut gemstone cost here?
Small fancy cuts such as the 21 carat ametrine and the 30.7 carat rutilated quartz cabochon open the range, mid weight citrines and tourmalines sit above them, and the largest untreated Brazilian topaz carries the highest figure on the page. The table above draws live from the catalogue, so each figure belongs to that individual gem rather than to a per carat average.
Are these gemstones natural or treated?
Astro Gallery states treatment in the description of every loose stone. The Brazilian blue topaz and the Brazilian amethyst here are catalogued as natural and untreated, the Madeira citrine is described as naturally coloured, and where a gem carries routine trade treatment the listing says so before you buy.
Can I buy a calibrated size for a mount I already own?
Send the millimetre footprint and depth your mount accepts and we will match it against current stock. Most gems on this page are one of one custom cuts rather than calibrated goods, so the honest answer for a stock semi mount is often that a goldsmith should adjust the head.
What is windowing and does it matter?
Windowing is the transparent washed out patch in the centre of a stone whose pavilion was cut too shallow to reflect light back. It matters because a windowed gem looks paler and duller once it is set, and our photographs are taken so you can judge that zone yourself.
Will you set a stone I purchase from this page?
Our gemstone desk works with bench jewellers and will discuss a mount for any loose gem you order. Tell us the metal, the style and the finger or chain size at the point of purchase, and we will quote the fabrication separately from the stone.
How do I order a gemstone I have only seen in photographs?
Request the extra media first, then complete the order through secure checkout in the usual way. We supply daylight video, a millimetre rule shot and a profile view of the girdle on request, and the piece stays in stock and reserved for you while you review them.
Will a faceted gem ship outside the United States?
Yes. Loose stones travel tracked and fully insured to the declared value worldwide, with customs paperwork completed before dispatch. Gem paper and a rigid inner box keep the stones separated, and the outer carton is double boxed.
Can I return a loose stone that does not suit the design?
Yes, under the terms published on our returns page, provided the gem comes back unset and in its original packaging. Asking for the millimetre readings and a daylight video beforehand settles the question for most buyers before a stone ever ships.

Loose Stones, Finished Jewellery and the Species Behind Them

Buyers arriving here split three ways: some want the species in any form, some want a specific cut, and some want the finished piece instead.

Other loose gemstone pages
GemstonesCitrine cut gemstonesAmber cut gemstonesGems and jewelry
The same species uncut
AmethystCitrineQuartzRuby
Set and ready to wear
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