Coral: The Ocean’s Sacred Jewel – A Comprehensive Guide

How to identify dyed coral vs. natural oxblood red?

Introduction

Coral (珊瑚 Shānhú), revered as “火樹” (Fire Tree) in ancient China, is the calcified skeleton of marine polyps. Celebrated as one of Buddhism’s “Seven Treasures” (七寶 Qī Bǎo), it symbolizes the Buddha’s compassion—scriptures like the Mahaprajnaparamita Sastra describe his tongue as “coral-red.” Archaeological finds, such as Han Dynasty (206 BCE–220 CE) coral beads from Shandong and Guangdong, attest to its enduring cultural significance.

Physical & Chemical Properties

Composition: CaCO₃ (aragonite form) + conchiolin (organic protein).
Hardness: 3–4 on Mohs scale (handle with care).
Density: 2.6–2.7 g/cm³.
Structure:
Microcrystalline: Concentric growth rings under magnification.
Colors: Ranges from white to deep “oxblood” red (iron oxides).
Optical Traits:
Luster: Waxy to vitreous.
UV Reaction: May fluoresce weakly.

Key Fact:
Only Corallium rubrum (Mediterranean) and Corallium japonicum (Pacific) are gem-quality.

Color Varieties & Grading

1. “Oxblood” Red (牛血紅)

Source: Mediterranean (Italy, Sardinia).
Value: Up to $5,000/kg for branch diameters >1.5 cm.

2. “Angel Skin” Pink (孩兒面)

Source: Taiwan Strait.
Cultural Status: Reserved for Qing Dynasty court beads.

3. White & Black Coral

Use: Buddhist prayer beads (mala).

Grading Criteria:

Color: Uniformity and saturation (no dye).
Size: Branches >30 cm tall command premiums.
Texture: Smooth, crack-free surfaces.

Historical & Cultural Significance

Imperial China:
Ming-Qing Era: Rank badges featured coral buttons for high officials.
Mythology: Believed to ward off storms (placed in ships’ keels).
Global Lore:
Tibetan Buddhism: Ground into medicinal powders.
Victorian Europe: Mourning jewelry symbolizing eternal life.

Sustainable Sources

Protected Species:
Mediterranean Red Coral: Harvesting now heavily restricted.
Pacific Coral: Taiwan’s PengHu Islands (regulated since 2019).
Ethical Alternatives:
Gilson Coral: Lab-grown calcium carbonate.

Craftsmanship & Modern Uses

Carving:
Traditional: “Guanyin” statuettes with flowing robes (red coral).
Innovation: Micro-engraved zodiac pendants.
Jewelry:
Setting Tip: Encapsulate in resin to prevent sweat damage.

Conservation Note:
Pre-1990s antique coral is more ethical than newly harvested pieces.

Why Coral?

Rarity: Decades to grow 1 cm in diameter.
Spiritual Legacy: Bridges Taoist immortality and Buddhist purity.

How to identify dyed coral vs. natural oxblood red? Explore coral’s depths at VirtuCasa.com.

Coral: The Ocean’s Sacred Jewel – A Comprehensive Guide