Iroishi Checker
No. 087 / 141
ReferenceREFERENCE
Red ZirconContribute a photo

Red Zircon

レッドジルコン · れっどじるこん
NaturalRed / Pink
Gemological dataPROPERTIES
Hardness6.5-7.5
Specific gravity4.65
Refractive index1.925-1.984
Crystal system正方晶系
Color rangeCOLOR RANGE

Orange-red, deep crimson, brownish red, and warm cinnamon tones. The most prized color is a saturated pure red with strong fire; brownish casts are common in lower-grade material.

UV responseFLUORESCENCE
Long-wave
365 nm
Yellow to orange in some material; many stones are inert
Short-wave
254 nm
Weak yellow; metamict material is inert
Typical inclusionsINCLUSIONS
  • Strain features from metamictization
  • nclusions
  • nclusions of monazite, xenotime, or apatite
  • Color zoning along growth planes
Optical characterOPTICAL TRAITS
  • Doubly refractive, uniaxial positive
  • Refractive index 1.92–2.01
  • 0.04–0.06 — pronounced at 10×
  • Specific gravity 4.6–4.7
  • 0.039 — strong fire
What to look forID POINTS
  1. 01Strong visible at 10× — separates red zircon from singly refractive ruby and garnet
  2. 02Refractive index above the refractometer scale (over-the-limit reading >1.81) confirms zircon
  3. 03Specific gravity 4.6–4.7 — heavier than both ruby (4.0) and pyrope-almandine garnet (3.7–4.2)
  4. 04Characteristic 653.5 nm uranium absorption visible through a hand spectroscope
Stones it gets mistaken forSIMILAR STONES
Natural Ruby
Natural Ruby
ルビー（天然）
Ruby has RI 1.76–1.77, SG 4.0, and shows no at 10×. Red zircon has RI 1.92–2.01 (off-the-scale on the refractometer), SG 4.6–4.7, and pronounced . The two are easily separated under loupe and refractometer.
Rubellite
Rubellite
ルベライト
Rubellite (red tourmaline) has RI 1.62–1.64, SG 3.06, and moderate . Red zircon has much higher RI, much higher SG, and stronger — the refractometer and hydrostatic balance both give clear separations.
Care & handlingCARE
  • Mohs 6.5–7.5 — durable enough for normal jewelry use, but edges chip easily; avoid impact and abrasion
  • Heat-treated stones may revert under prolonged UV — store away from sunlight
  • nclusions are vulnerable
Market notesMARKET
PRICE RANGE

¥5,000–15,000/ct for commercial Cambodian heat-treated material, up to ¥40,000–60,000/ct for fine Sri Lankan stones with pure red color above 3 ct.

Note: Heat treatment to enhance red color from brown rough is common and disclosed. The chief market concern is the same zircon-versus-CZ consumer confusion that affects every zircon color — explicit identification as natural zirconium silicate is essential at sale. Genuinely fine large stones (above 5 ct) in pure red without brownish casts are scarce and command premium prices.

BackgroundBACKGROUND

Red zircon is zirconium silicate (ZrSiO₄, tetragonal) colored orange-red to deep red by trace uranium and titanium, with iron contributing brownish tones. The mineral takes its English name 'hyacinth' (and the medieval variant 'jacinth') from the Greek hyakinthos — both the mythological youth slain by Apollo's discus and the flower said to have grown from his blood. Medieval European lapidaries did not distinguish red zircon from similarly colored red garnets and red corundum, and 'hyacinth' was applied loosely to all three. RI 1.92–2.01, SG 4.6–4.7, Mohs 6.5–7.5, 0.039.

Origin & historyORIGIN & HISTORY

Origins

Sri Lanka (Ratnapura, Elahera) is the classical source and continues to produce the finest crimson-to-cinnamon hyacinth zircon. Myanmar (Mogok), Cambodia (Ratanakiri), Tanzania, and Madagascar contribute additional production. Sri Lankan stones tend toward pure red with strong fire; Cambodian material is more orange-toned and is frequently heat-treated.

History

Hyacinth zircon appears in Pliny's Naturalis Historia (77 CE) as a red gem and is the eleventh foundation stone of the New Jerusalem in the Book of Revelation (21:20). It was widely used in medieval European ecclesiastical jewelry — reliquaries, episcopal rings, monstrances — and is recorded among the gems of the Hungarian Holy Crown of St. Stephen (early 11th century), one of the foundational pieces of Christian European royal regalia. The systematic separation of red zircon from red garnet and red corundum came only with 19th-century gemology.

Lore & symbolism

Medieval European tradition associated jacinth with sleep — the stone was said to dispel insomnia and protect travelers — and the Renaissance lapidary of Camillus Leonardus (1502) prescribes it against melancholy and plague. The biblical association with the New Jerusalem gives the stone an enduring Christian symbolism of celestial reward. Sanskrit tradition links red zircon with Surya (the Sun) and prescribes it as a planetary remedy for solar deficiencies in Vedic jyotish.

OBSERVATION TOOLS · 2 ITEMS

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Tools that help confirm Red Zircon. Tap any item to jump to the matching section on the gem tools page.

References
最終確認日
2026年4月28日
参 考 文 献

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