Columnar basalt forms wherever lava cools quickly enough to contract uniformly. The geometry is not random: the cracks propagate at roughly 120-degree angles to minimize stress, producing the characteristic hexagonal and polygonal shapes. At Gành Đá Đĩa, the process was complicated by the presence of the sea. Wave action fractured the vertical columns horizontally over thousands of years, producing the disk-like surfaces that give the site its name. Two distinct promontories resulted. The northern one shows inclined and curved columns — evidence of lava flows that cooled under different pressures or gradients. The southern promontory has mostly upright columns that step down in levels from high ground to the waterline, like a natural amphitheater facing the sea.

Science and folklore arrived at the same striking image independently. Where geologists see polygonal cracking and horizontal fracturing, local legend sees plates: specifically, the golden bowls and jade dishes that immortals left behind after a celestial banquet, forgetting them on the coast and allowing them to slowly petrify. A second legend offers a more dramatic origin — a treasure hoard of gold and jewels set ablaze by thieves, then transformed into stone by a whirlwind and explosion. Neither account is wrong in the sense that matters: both register how unusual this formation looks, how deliberate, how unlike ordinary rock. The site earned Vietnam's National Scenic Site designation in January 1997 and was elevated to National Special Relic status in December 2020.

At the southwestern edge of the formation, a small temple stands where the columns meet the land. Lăng Đá Đĩa was built around the mid-19th century during the reign of Emperor Tự Đức, dedicated to the worship of Nam Hải — the Whale God, a deity central to the maritime culture of coastal Vietnamese fishing communities. Fishermen across Central and South Vietnam historically venerated whales as protectors, sometimes conducting formal funerals when a whale stranded. Building a temple at this particular spot — where the ocean has visibly shaped the rock over millennia — was not accidental. The site already carried weight. The temple gave that weight a ritual form.

Comparisons to Northern Ireland's Giant's Causeway are inevitable and apt. Both formations are basalt, both columnar, both coastal, both protected as national heritage sites. The differences are in the light and the water. At Giant's Causeway, the columns emerge from cold Atlantic surf under frequently overcast skies; at Gành Đá Đĩa, the same dark geometry rises against a tropical coast where the water is a deep clear blue and the sunlight angled and intense. The columns here are darker, their surfaces more varied — some worn smooth by surf, others still sharp where fracture lines remain fresh. At low tide, when the water retreats from the lower terraces, the full extent of the formation becomes visible: row after row of geometric pillars, a coastline that looks assembled rather than grown.