What are cave pearls? (And 14 more unusual cave formations)

What are cave pearls, exactly? Learn about these unusual rock formations and 14 more in our guide.

They're pretty common, usually white in colour and tend to chill about with frostwork or other needle-like formations.

But whatever you do, don't eat it. 

5. Dogtooth spar

Dogtooth spar formations are named as such due to their resemblance to dog's teeth – you'd never have guessed that would you?

These large calcite crystals come to be through mineral precipitation. You can find them in caves as well as geodes.

A cave full of teeth… not scary at all…

6. Flowstones

One of the most majestic types of cave formations in the world, flowstones are deposits of calcite and other carbonates that form flowing sheetlike deposits. 

They're formed when mineral-rich water flows down cave walls or along cave floors. You can usually spot them in limestone caves. Some of the most impressive formations at Stump Cross Caverns are flowstone formations.

7. Calcite rafts

Just imagine for a second how peaceful it would be to be a calcite crystal raft floating along in cave water. These cool crystals form on the surface of quiescent (stagnant) water, joining together as they grow.

They're usually white or opaque and have been called 'leopard spots'. Very chic.

8. Helictites

Considered to be one of the most delicate cave formations, these curving, angular wonders are rarely seen in caves that tourists can visit. Or, at least, not within arm's reach.

Helictites form many intriguing shapes because they grow in different directions at various stages of their development. These types of formations have earned many colourful names, including:

• Fishtails
• Ribbons
• Saws
• Rods
• Butterflies
• Curly fries
• Clumps of worms
• Hands

9. Soda straws

Fancy a sip? Nature has created stunning straw-like cave formations in the shape of hollow cylindrical tubes.

Also known as tubular stalactites, these straws grow in caves in areas where water slowly leaches through the cracks in rocks. You're most likely to spot them on cave roofs.

10. Chandeliers

Some caves are fancier than others, displaying magnificent claw-like gypsum stalactites with large crystals on the ends of them. 

These formations are quite rare – they're only witnessed in a few caves in the southwestern USA. That includes the Lechuguilla Cave in New Mexico, which houses the largest and most impressive cave chandelier ever discovered.

11. Fried egg stalagmites

How do you like your eggs? If you like them fried, you might want to check out these tasty-looking wonders.

These unique formations have a disc shape with a round yolk-like central depression. They're formed when calcite-rich water falls onto pre-existing stalagmites.

12. Snottites

Bless you! Snottites, also known as "snoticles", look like something you'd see hanging from someone's nostrils rather than cave walls and ceilings.

Composed of single-celled bacteria, these formations have the consistency of – you guessed it – snot.

Professor Brian Cox examined these yucky phenomena and claimed that if there was life on Mars, it would probably be similarly primitive to snotties.

13. Hells Bells

Ding, dong! Hells Bells are hollow bell- or cone-shaped carbonate structures that can reach a whopping two metres long. 

These slightly eerie wonders are thought to be formed through complex interactions between cave water and the microorganisms that live amongst it. They thrive in toxic environments and were named after the AC/DC song "Hells Bells" by cave divers. Rock 'n' roll!

14. Lava tubes

A bit like a naturally formed London Underground, lava tubes are what's left over when a lava stream path becomes empty. They're formed when low-viscosity lava creates a hard crust in the earth that thickens and forms a roof over flowing lava. 

These formations can be up to 15 metres wide and extremely long. The lengthiest known tube is the 31-mile-long Manua Loa, which enters the ocean.

15. Curtains

You wouldn't think caves need curtains, since they're so dark already. However, nature decided to bestow them with some drapes anyway.

These calcite formations flow down from cave roofs and walls in a wavy shape that looks like hung curtains – with some looking like strips of bacon.

We've got a pretty cool one here at Stump Cross Caverns called The Curtain. This thin sheet of rock features dazzling red streaks that look like a dragon's wing.

Now you know about the coolest cave formations, why not come and see what you can spot here at Stump Cross Caverns? Explore some of the best-preserved prehistoric caves in the UK full of fascinating formations like The Twins, The Curtain, and the colourful stalactites in The Butcher's Shop. Book your tickets today.