Every shop in this trade, including this one, sells things whose names are doing some work. That is not usually a lie. It is a convention, and the convention is old. But you are the one paying, so here are the five tests, all of which you can do at your kitchen table, and none of which require a loupe.
1. Glass or quartz: use your cheek, then your fingernail
Quartz conducts heat away from your skin roughly ten times better than glass does. Hold a sphere against your cheek. Real quartz feels properly cold and stays cold for a few seconds before it warms. Glass goes to skin temperature almost at once. Do the same with two objects side by side and the difference is obvious.
Then look inside, into a lamp. Glass traps round bubbles, because gas rises through a melt as a sphere. Quartz traps irregular things: feathery veils, flat fracture planes, wisps that end in a point. If every inclusion is a neat circle, you are holding glass.
None of which makes it a bad object. A cast optical-glass sphere is more optically perfect than almost any natural quartz you could afford, which is exactly why scrying balls are usually made of it. It just is not stone.
2. Dyed stone: look in the cracks
Dye travels through a stone the way water travels through a pavement — along the fissures. So on a dyed piece the colour is deepest in the cracks and palest in the solid areas, which is the reverse of how natural colour behaves. Look at the drill hole on a bead: if the inside of the hole is darker than the surface, it was dyed after drilling.
The classic case is white howlite dyed blue and sold as turquoise, sometimes under the trade name "turquenite". Howlite is naturally chalk-white with grey veining. Turquoise is not.
3. Selenite: your fingernail settles it
Selenite is gypsum, and gypsum sits at 2 on the Mohs scale — below a fingernail, which is about 2.5. You can scratch genuine selenite with your thumbnail and leave a mark. If you cannot, it is not selenite.
The same softness is why every piece of selenite we sell carries a warning not to wash it. Gypsum is soluble. Water does not clean it; water dissolves it, slowly and permanently.
4. Precious metal: the law is on your side
This is the one most people do not know. Under the Hallmarking Act 1973, if you sell an article in the UK in the course of trade and describe it as silver, gold, platinum or palladium above the exemption weight, it must carry a UK hallmark. The thresholds are 7.78g for silver, 1g for gold and palladium, and 0.5g for platinum.
So a 20g bracelet described as "925 silver" is legally required to be hallmarked. A 4g pair of earrings is not. That is a real, checkable line, and it is worth knowing before you spend three figures on something described as sterling.
Second test, free: arithmetic. Gold is priced per gram and everybody pays the same for it. If a piece described as "18k gold and 925 silver" weighs twenty grams and costs a hundred and thirty pounds, the gold is a plated surface layer. It cannot be anything else. Plating is a perfectly good finish — Balinese silversmiths have used it for generations — but it should be described as what it is.
5. "Crafted", "reconstituted", "created": read the adjective
Trade language is precise when it wants to be. A crafted cluster is assembled from separate points rather than lifted from the ground as one piece. Reconstituted stone is ground rock bound with resin. Created means grown in a laboratory, which for something like quartz produces a chemically identical crystal.
Any of those can be the right purchase. A crafted cluster gives you an even, balanced spread that a natural specimen at the same price never would. The word is there to tell you, and the seller has done nothing wrong by using it. The trick is knowing it means something.
What this shop does about it
We apply the five tests to our own listings before you have to. Our 20cm sphere is described as K9 optical glass in its first sentence, not as a crystal ball. Our Balinese silver says the gold is a surface layer. Five devotional pendants were renamed when their own supplier documentation described the stones as amethyst-coloured.
We would rather tell you and lose the sale.