Jewellery VideoPart of the JDMIS learning network

Watch, learn, make — video-first jewellery education from JDMIS

Gem knowledge

The hardest gemstones — Mohs 8 and above for everyday wear

Mohs 8+ is the daily-wear club — here is who makes the cut.

For rings that never come off, Mohs 8+ is the club. The members:

  1. Diamond — 10. The benchmark; scratches everything, careful of
    cleavage along crystal planes.
  2. Corundum — 9 (sapphire & ruby). The practical wear champion; every
    colour available somewhere in the family.
  3. Moissanite — 9.25. The synthetic daily-wear alternative
    (compared).
  4. Chrysoberyl — 8.5 (alexandrite, cat's eye). The collector's durable
    gem.
  5. Topaz — 8. Hard but cleaved — hardness is not toughness
    (explained).
  6. Spinel — 8. History's red "ruby" impostor, now its own celebrated
    gem; excellent wear.

What Mohs does NOT promise — toughness (diamond cleaves), chemical
stability (pearls laugh at hardness from their shelves), or beauty (cut
and colour outrank the number). Full context in the gemmology course.

Go deeper — free

Watch the free replays at the gem webinar library — the gem e-book is the written companion. When curiosity becomes commitment, the gemmology foundation course is the ladder's first rung (online entry: GT100e); dates on the calendar. Play Name That Gem to train the eye between sessions.

What students say

“I will use the skills learnt to make jewellery and other items, such as phone chains, christmas tree decorations & hopefully sell them.”

— Nadia W. (England) · published student feedback

“I will use the skills learnt to draw more designs for my company as we are now dealing a lot in fancy cut diamonds.”

— Darvina P. (Singapore) · published student feedback

Free ways to explore

No sign-up, no payment — start with any of these.

WWatch a free gem webinarFREE
Full recorded sessions — the best free starting point.JJDMIS on YouTubeFREE
Course previews, blended-learning explainers and school life.FFree jewellery webinar replaysFREE
Recorded sessions on design and the jewellery industry.DDownload the gem e-bookFREE
The school's free guide to gems — pairs with the replays.

Keep exploring

How gems are graded — colour, clarity, cut, weight beyond diamondsHow coloured gemstones are graded — colour first, then clarity by species, cut quality andAmber and coral — the organic gemsAmber and coral explained — fossilised resin and living skeleton, the treatment and imitatBirthstones by month — the video-era gift guideThe twelve birthstones with colours, hardness and gift notes — the fastest way to personalGem treatments explained — heat, oil, filling and diffusionThe gem treatment landscape explained — heat, oiling, filling, irradiation and diffusion —

See the online and blended options

Gemmology can be started fully online, and every classroom course at JDMIS has a video-supported path.

Visit jdmis.edu.sg