1. I chose Tufa which is cheap and easily obtainable and quite a good substitute for real coral rock.

2. The rock mixture is 80% tufa rock and 20 percent living rock. Undergravel filtration is powered by two Aquaclear 402 powerheads.

3. These pale gray and ivory "tufa towers," located in California's Mono Lake, may look like eerie art instillations, but they occur naturally and are made of limestone.

4. The odd shapes that tufa take can sometimes resemble coral.

4. try its best to collect and create good sentences.

5. Mono Lake's tufa are particularly dramatic because water diversions have significantly lowered the lake's level, exposing more of the columns.

6. They were carved from locally quarried tufa—a soft volcanic stone—between 800 and 1722, when a Dutch explorer discovered the island.

7. Made of limestone, tufa forms as a byproduct of the precipitation of carbonate minerals from surrounding water.

8. Spires of limestone tufa rise from the shores of California's Mono Lake.

9. The uncanny tufa formations take on a golden appearance at sunset.

10. The delicate white tufa towers formed where freshwater springs percolate up from the bottom of the lake.

11. Tufa, the unusual rock formations that jut out of Mono Lake in California's Eastern Sierra, are famous for their otherworldly beauty.

12. Another strangely beautiful early morning shot of the tufa formations, with the Sierra Nevada Mountains in the background.

13. Before this alkaline lake went dry, tufa formed when a freshwater spring percolated from below and formed calcium carbonate deposits.

14. The tufa towers rise like giant sand castles, peeking above Mono Lake's surface.

15. A sunset casts a warm glow over the tufa formations as seagulls forage for dinner.

16. The enormous necropolis is adjacent and contains hundreds of tombs cut down into the tufa over a distance of two miles.

17. Sierra Nevada as a backdrop, unique erosion formations called sand tufa stand like giant cauliflower stalks in a dry Arizona lake bed.

18. Mono Lake's tall grasses and shrubbery are shown growing along the bottom of this tufa formation.

19. So, the appropriate geochemical condition and the advantaged water dynamic condition compose the growth of the tufa of Wang 4 well.

20. With the snow-draped Sierra Nevada as a backdrop, unique erosion formations called sand tufa stand like giant cauliflower stalks in a dry Arizona lake bed.

21. In petrographic terms, this stone is defined as volcanic tufa.

22. The more recent calcareous, or calcium carbonate, deposits that make up the tufa formations are closer to the bottom and lighter in color.