Real or Fake? How to Check a Gemstone Before You Buy

Short answer: you can screen out most fakes at home with a 10x loupe, daylight and common sense. Natural stones usually show small inclusions and slightly uneven colour; glass shows round bubbles and swirls; and any vivid, flawless stone at a very low price deserves suspicion. These checks will catch most glass and many cheap imitations, but they cannot reliably catch good synthetics or hidden treatments. For a valuable stone, or one bought for astrological wear, an independent laboratory report is the only real proof.

This guide explains what "fake" can actually mean, the safe checks you can do yourself, the specific signs to look for in the stones Pakistani buyers ask about most, the "tests" you should never try, and when a laboratory report is worth getting.

What "fake" can mean

Not every non-natural stone is a scam. The problem is when a stone is sold as something it is not.

Type	What it is	Example	Fair if...
Imitation	A different material that only looks similar	Glass, plastic, cubic zirconia, dyed quartz sold as emerald, garnet sold as ruby	Sold under its real name at its real price
Synthetic (lab-grown)	Same chemistry and structure as the natural gem, made in a factory	Flame-fusion ruby and sapphire (made since the early 1900s), hydrothermal emerald	Clearly labelled as synthetic; never acceptable for astrological wear
Treated natural	A real stone whose appearance has been improved	Heated sapphire, oiled emerald, dyed agate	The treatment is disclosed and priced in
Composite	Pieces joined or filled to look like one stone	Opal doublets and triplets, lead-glass-filled ruby, reconstituted turquoise	Clearly described as a composite

Our gemstone buying guide explains which treatments are generally accepted and which ones change what a stone is worth.

Six safe checks you can do at home

1. Start with the price

This sounds unscientific, but it is the most reliable first filter. Big, vivid, eye-clean precious stones are rare everywhere in the world. A large, flawless "neelam" or "yaqoot" at a bazaar-trinket price is almost certainly synthetic, glass or heavily treated, whatever the seller says. Compare the price per carat (price divided by carat weight) across stones of similar quality.

2. Look inside with a 10x loupe

An inexpensive jeweller's loupe is the most useful tool a buyer can own.

• Natural stones often show tiny crystals, fine needles (silk), healed fractures shaped like fingerprints, or straight, angular colour zones.
• Glass often shows round or stretched gas bubbles and swirl marks.
• Flame-fusion synthetics may show curved growth lines (natural crystals grow in straight lines) and sometimes bubbles.

3. Compare colour in daylight

Take the stone to a window. Natural colour is often slightly uneven: banded, zoned, or stronger at one end. Glass and many imitations look flat and perfectly uniform. Be wary of a stone that looks spectacular under a shop's spotlights and dull at the door.

4. Feel temperature and weight

Crystalline gems draw heat from your skin, so sapphire, ruby, topaz or quartz feels cool for a moment when touched to the lip. Glass and plastic warm up faster. Corundum (sapphire and ruby) is also dense, so a stone that feels light for its size is suspect. This is a hint, not a test, and you need experience to use it.

5. Inspect the facet edges

Under a loupe, a hard natural stone usually has crisp facet junctions. Moulded glass often has slightly rounded edges, and worn glass shows small chips along the edges because it is soft.

6. Try the print test (for faceted transparent stones)

Place the stone table-down on printed text. A well-cut stone with a proper pavilion breaks up the text so you cannot read it. A see-through stone where the print is clearly legible may be badly cut, or it may be glass. Treat this as a clue only.

Stone-by-stone warning signs

Blue sapphire (neelam) and ruby (yaqoot)

Look for silk, angular colour zones and small crystals. Curved growth lines and bubbles suggest a flame-fusion synthetic; bubbles and swirls suggest glass. In ruby, coloured flashes along cracks and flattened bubbles inside them point to lead-glass filling. A perfect "pigeon blood" ruby at a low price is almost always filled or synthetic. More in our ruby guide.

Emerald (zamurd / panna)

Natural emerald normally shows inclusions – fingerprints, crystals and sometimes three-phase inclusions. Oiled fractures can show a slightly different sheen; resin-filled ones may flash colour as you tilt the stone. A clean, deep green emerald at a low price is likely synthetic (hydrothermal synthetics can show chevron-shaped growth lines), glass or dyed quartz. See how to identify a natural emerald.

Yellow sapphire (pukhraj)

The corundum signs above apply. In addition, fake pukhraj is often citrine, yellow topaz, yellow glass or yellow cubic zirconia. Citrine is lighter in the hand; glass shows bubbles; cubic zirconia throws strong rainbow flashes that sapphire does not. Browse genuine stones in the pukhraj collection.

Opal

Natural opal shows patches of colour that shift and flow as you move it. Synthetic opal often has an over-regular "lizard skin" or columnar pattern; glass imitations show fixed glittery flecks. Check the side: a thin layer of opal glued to a dark backing is a doublet, or a triplet if it has a clear cap, and should cost far less than solid opal. See the opal collection.

Pearl (moti)

Rub a pearl gently against the edge of your front teeth: natural and cultured pearls feel slightly gritty because of their layered nacre, while most imitations feel smooth. Under a loupe, real nacre shows fine, wavy ridges; imitation coatings look grainy and often flake around the drill hole.

Turquoise (feroza), lapis lazuli and agate (aqeeq)

Opaque stones are often dyed, stabilised, reconstituted from powder and resin, or replaced with dyed howlite or plastic. Look for colour concentrated in cracks and pits, which suggests dye. Natural feroza shows irregular colour and matrix; reconstituted material often looks too even. Natural lapis lazuli has metallic pyrite flecks that sparkle under a loupe rather than looking painted. Natural aqeeq shows soft, slightly wavy banding.

"Tests" you should never try

• Scratch tests. They can permanently damage a genuine stone, and hard imitations such as cubic zirconia and synthetic corundum will pass anyway.
• Flame or heat tests. Heat can crack emerald and opal, change the colour of some stones and damage glass-filled ruby, and tells you nothing a loupe cannot.
• Acids, bleach or strong solvents. These can ruin pearl, turquoise, lapis and other porous or soft stones.
• Social-media tricks. "Water tests", "hair tests" and similar folklore prove nothing either way.

When to get a laboratory report

Ask for an independent gemmological report that states the species, whether the stone is natural or synthetic, and any treatment, when:

• the stone is valuable enough that a mistake would really hurt;
• you are buying it for astrological wear, where tradition requires a natural stone;
• the seller claims a premium origin such as Kashmir, Burma or Colombia;
• the stone is described as unheated or untreated, which adds to the price.

At GemStore, a certificate of authenticity is available on request, and we can arrange independent laboratory testing. See how we check stones on the authenticity page.

What natural means at GemStore

We sell natural loose gemstones only. We inspect every stone before listing it, photograph it as it is, price it individually and disclose treatments that are normal for that gem, such as heating or oiling, when they are known. You can pay Cash on Delivery and open the parcel to inspect the stone before paying, and our 7-day return policy applies if a stone is not as described. Explore the full collection, or contact us with questions about any stone before you order.