Gemstones Worth Collecting.
Loose gemstones chosen by house gemologist, rated on a transparent 1–50 collector scale and documented stone by stone — so you can collect with understanding, not guesswork.
Individual Gemstones
Slideshow
The Otzera 50
A transparent 1–50 collector rating that turns professional judgment into something you can compare. It is our rating within a species — not a laboratory grade or a price guarantee.
A permanent record
Every stone carries a unique ID and a QR-linked passport holding its identity, disclosures, media and evaluation. The record stays live long after the sale.
Founder-led curation
Selected stone by stone by a gemologist with laboratory, auction-house and teaching experience — never bought in bulk to make a catalog look large.
The Otzera 50
How we read a stone
Colored gemstones have no universal grading system — the variables are too complex for one scale. The Otzera 50 is our answer: fifty points, weighted toward beauty and always judged relative to the species.
- Color
- Cut & Optical Performance
- Clarity & Transparency
- Rarity & Collectibility
1–10
Common
11–20
Standard
21–27
Discovery
28–34
Collectible
35–40
Distinguished
41–45
Signature
46–50
Exceptional
Color and cut together account for close to two-thirds of the score, because beauty is why gemstones matter. Origin, treatment and documentation are disclosed in full and can add collector significance — but they never outweigh the stone itself. A high score does not mean a high price, and a modest stone can rate strongly within its own kind.
See the rating system
Meet the gemologist
Otzera is led by Eitan Tashey, whose work across gemological laboratories, international auction houses and gemstone teaching shapes every selection. The person who chooses each stone is the same person who evaluates it, describes it and stands behind it.
Digital Gem Passport
Know the Gem. Own the Story.
Every Otzera gemstone carries a permanent record — its gemology, its O50 evaluation and the reasoning behind the score. Enter the Otzera ID from your gemstone to open its passport.