The Gemstone Codex is a free public knowledge resource covering every commercially significant coloured gemstone, built to the standard that serious buyers, Jyotish practitioners, gem students, and collectors deserve but rarely find in one place.
The gem market has a knowledge asymmetry problem. Sellers know significantly more than buyers, and that asymmetry produces fraud, overpayment, and disappointment at enormous scale. The Gemstone Codex exists to reduce that asymmetry. Every article is written to give the reader what a knowledgeable, honest gem dealer would tell them before they spend money: what matters, what does not, what the risks are, and how to protect themselves.
The Codex covers 86 articles across 23 gem species and 12 subject hubs, from the optical physics of colour change in alexandrite to the specific quality requirements in Sanskrit Jyotish texts. The standard applied throughout: no claim without a verifiable source, no recommendation without acknowledging its limits, and no simplification that misleads.
Every factual claim in the Codex is cited to a verifiable primary source. The primary sources are: GIA Gem Reference Guide (2006); GIA Gems and Gemology journal; Gübelin Gem Lab; AGL; SSEF; Lotus Gemology; Hughes R.W., Ruby and Sapphire (1997, 2017); Nassau K., The Physics and Chemistry of Color (2001); Nassau K., Gems Made by Man (1980); Wise R.W., Secrets of the Gem Trade (2016); Schmetzer K., Russian Alexandrites (2010); Kautilya, Arthashastra (c. 300 BCE); the Brihat Samhita (c. 550 CE); Behari B., Gems and Astrology (1991); Johari H., The Healing Power of Gemstones (1986); GJEPC; CIBJO; AGTA; Christie's Geneva; Sotheby's Geneva; AMNH; Smithsonian; V&A; Ogden J., Jewellery of the Ancient World (1982); and others. The full source list is at sources.html.
The Gemstone Codex is not a gem dealer, a laboratory, or a valuation service. It does not recommend specific purchases, certify specific stones, or provide individual investment advice. The Jyotish content provides the gemological framework for implementing practitioner recommendations; it does not provide Jyotish advice itself. The investment content provides the market framework for informed decisions; it does not constitute financial advice. The buying guides provide general protective frameworks; they do not substitute for independent gemological examination of specific stones.
The Gemstone Codex (claradiam.com/gems/) is part of Claradiam, the diamond and gemstone knowledge platform. Claradiam also includes The Diamond Codex (claradiam.com), covering diamonds in equivalent depth. Both are built and maintained by Clicarity, a knowledge and media company based in India.
Corrections, source challenges, and substantive feedback are welcome via WhatsApp at +91 99205 10234. We correct errors when presented with better evidence. The Codex improves through scrutiny.