Ruby & Sapphire: The Royal Gemstones – A Complete Guide

Best sapphire cuts to minimize color zoning

Introduction

Ruby (紅寶石 Hóngbǎoshí) and sapphire (藍寶石 Lánbǎoshí) are gem varieties of the mineral corundum (Al₂O₃), revered across civilizations for their vivid hues and rarity. While rubies are defined by their chromium-induced red, sapphires encompass all other colors—blue (from iron/titanium), yellow (iron), and even rare “padparadscha” orange-pink. Historically, these gems adorned royal regalia, from Byzantine emperors to Ming Dynasty hairpins (e.g., gem-embedded gold hairpins from Xu Da’s tomb, 15th century).

Physical & Chemical Properties

Hardness: 9 on Mohs scale (second only to diamond).
Density: 3.9–4.1 g/cm³.
Crystal System: Hexagonal, forming barrel-shaped prisms.
Optical Traits:
Refractive Index: 1.76–1.78.
Pleochroism: Rubies show red-purple; blue sapphires exhibit blue-green.
Inclusions:
Rubies: “Silk” (rutile needles) enhances asterism (star effect).
Sapphires: Hexagonal color zoning indicates natural origin.

Color Varieties & Valuation

Rubies

Pigeon’s Blood (緋紅色):
Color: Vivid red with faint blue undertones (exclusive to Myanmar’s Mogok Valley).
Value: Up to $1M/carat for untreated >5ct stones.
Rose Red: Common in Thai deposits (darker due to iron).

Sapphires

Kashmir Blue (矢車菊藍):
Color: Velvety cornflower blue (mined briefly in 1880s).
Rarity: Auction records exceed $200,000/carat.
Padparadscha (蓮花剛玉):
Color: Sunset-like pink-orange (Sri Lankan origin).

Grading Criteria:

Color: Hue, saturation, tone (e.g., “royal blue” > “light blue”).
Clarity: Eye-clean preferred, but silk boosts ruby value.
Carat: Prices rise exponentially >3ct.

Historical & Cultural Significance

China: Ming Dynasty (1368–1644) imported Burmese rubies for imperial jewelry.
Europe: Medieval clergy wore sapphires to symbolize heaven.
Science: First synthetic rubies (1902) led to laser technology.

Global Sources

Rubies:
Myanmar (Mogok): 90% of pigeon’s blood supply.
Mozambique: Rising source of high-clarity stones.
Sapphires:
Sri Lanka: All colors, including rare color-changers.
Australia: Dark blue (often heat-treated).
China: Shandong’s blue sapphires (1980s discovery), though historically relied on imports.

Treatments & Ethics

Heat Treatment: Common to enhance color/clarity (must be disclosed).
Lead Glass-Filling: Low-quality rubies—avoid (fragile, devalues).

Craftsmanship & Modern Uses

Jewelry:
Rubies: Best in bezel settings (protects inclusions).
Sapphires: Step cuts (emerald) maximize color depth.
Technology: Synthetic corundum in watches and optics.

Cutting Tip: Orient rubies to show pure red (avoid “extinction” dark areas).

Why Ruby & Sapphire?

Durability: Ideal for heirloom pieces.
Symbolism: Rubies = passion; sapphires = wisdom (per Lapidarius texts).

Best sapphire cuts to minimize color zoning. Explore royal gems at VirtuCasa.com.

Ruby & Sapphire: The Royal Gemstones – A Complete Guide