Blog posts of '2014' 'March'

Mohs' hardness and 'spring' cleaning gemstones - part 1

You may have wondered why you find the Mohs' scale of hardness in the description of the gemstones. The hardness or the resistance to scratches determines the durability of the gemstone.

The German born mineralogist Friedrich Mohs (1773-1839), student of Abraham Werner, developed a scale that measures the scratch resistance from hard on soft minerals. The scale goes from 1 to 10, talc being the softest (1) and diamond being the hardest (10). With your fingernails, which have a hardness of 2.2, you may scratch talc.

As a consequence when cleaning your gemstones and jewelry you need to take into account their scratch resistance so as not to damage them.

Care about your porous gemstones. Do not spray cosmetics or perfume while wearing them, chemicals may damage them.


Mohs' hardness          Ultrasonic**          Soap***          Untreated cloth°

  • Agate**                      6.5 – 7.0                 No                        Cold water           Yes
  • Amazonite                   6.0 – 6.5                 No                        Yes                     Yes
  • Amethyst                    7.0                          Normally yes         Yes                     Yes
  • Aquamarine                7.5 – 8.0                  Normally yes         Yes                     Yes
  • Carnelian                    7.0                          Normally yes         Yes                     Yes
  • Citrine                        7.0                          Normally yes         Yes                     Yes
  • Coral                          3.5 – 4.0                  No                        No soap              Yes
  • Diamond                    10.0                         Yes                       Yes                     Yes
  • Emerald                     7.5 - 8.0                   No (fracture risk)   Yes                     Yes
  • Fluorite                      4.0                           No                        Yes                     Yes
  • Garnet                       7.0 – 7.5                  Normally yes          Yes                     Yes
  • Howlite                      3.0 – 3.5                  No                         Yes                     Yes
  • Jade, jadeite               6.5 – 7.0                 Yes                        Yes                     Yes
  • Jade, nephrite             6.0 – 6.5                 Yes                        Yes                     Yes
  • Kyanite                      4.0 – 7.5                  No                         Yes                     Yes
  • Labradorite                 6.0 – 6.5                  No                        Yes                     Yes
  • Lapis-lazuli                 5.0 – 6.0                  No                         Yes                     Yes
  • Malachite                   3.5 - 4.0                   No                         Yes                     Yes
  • Moonstone                 6.0 – 6.5                  No                         Yes                      Yes
  • New jade                   2.5 – 5.5                  No                         Yes                      Yes
  • Opal                          5.0 – 6.5                  No                         Yes                      Yes

SEE - part 2

Mohs' hardness and 'spring' cleaning gemstones - part 2


Mohs' hardness          Ultrasonic**          Soap***          Untreated cloth°

  • Pearls                          2.5 – 4.0                 No                        No                       Yes
  • Peridot                        6.5 – 7.0                 No                        Yes                      Yes
  • Rhodochrosite              3.5 – 4.5                 No                      Cold water             Yes
  • Rhodonite                    5.5 – 6.5                Normally yes          Yes                      Yes
  • Ruby                           9.0                         Yes                       Yes                      Yes
  • Sapphire                      9.0                         Yes                       Yes                     Yes
  • Serpentine                  3.0 – 5.0                  No                        Yes                     Yes
  • Shell                           3.5                          No                        Yes                     Yes
  • Sodalite                      5.0 – 6.0                  No                        Yes                     Yes
  • Tanzanite                    6.0 – 7.0                 No                        Yes                     Yes
  • Topaz                          8.0                         No                        Yes                     Yes
  • Tourmaline                  7.0 – 7.5                 No                        Yes                     Yes
  • Turquoise                    5.0 – 6.0                 No                        Yes                     Yes

* Most agate beads are enhanced or dyed – rinse them briefly under running water before the actual stringing!

** In doubt, ask your jeweler.

*** Soap : lukewarm water, mild soap, soft toothbrush – dry° - never soak soft porous gemstones!

Moh's scale of hardness

A few tips:

  • Do not clean over the sink, you may lose small items.
  • Do not store before completely dry.
  • Vintage jewelry is best cleaned by professionals.
  • Diamond, ruby, sapphire: add a splash of ammonia in clear water to remove all film and give back its sparkle – never do this with other gemstones!

Thank you for choosing your beads and findings @ http://dunebeads.com/en/ !

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March's birthstones - In need of some luck ... Bloodstone and aquamarine

Happy birthday to you, March child. Your birthday flower, the wild jonquil(le) or narcissus jonquilla, which delivers a lovely fragrance oil, has clusters of small golden yellow trumpet flowers with a crown and long narrow cylindrical leaves.

The jonquil stands for spring and means 'friendship' and 'domestic happiness or returned love'. In Victorian times, its hidden message was 'you are an angel'... and aren't we all. :-)

Your lucky stone or modern birthstone is a blue-green beryl, the aquamarine, which means 'water of the sea'. Its color, produced by traces of iron, ranges from very light green-blue to deep blue-green; the dark blue or sapphire blue version being called maxixe is sometimes heat treated to create green, pink or yellow beryl. As deep sky blue aquamarine is considered more valuable than the clear or green shades, most blues have also passed the heating process to deepen their color and remove the green tint.

For the amateur aquamarine looks very similar to blue topaz, but as it is more valuable, you'd better buy your set stones from a trustworthy jeweler.

Aquamarine stands for courage, faithfulness & friendship and is the lucky stone of sailors. It is also said to facilitate communication.

Your alternative traditional gemstone is the two-toned heliotrope or Bloodstone and means 'sun turning'. It shares its name with the flower which was supposed to turn towards the sun. It is a form of dark green to dark blue-green chalcedony with red to red-brown iron-oxide inclusions. The green tends to have darker and lighter zones. The red is due to iron oxide, such as hematite, while the green is formed by Chlorite minerals, sediments of marine water, in the cryptocrystalline (very fine grained) quartz. The dark green variant with yellow spots is called plasma. Heliotrope is usually not enhanced.

It is said that heliotrope gives courage and strength. It should heal a broken heart and bring good luck.

So a very 'lucky' birthday to you and enjoy the sea!

Who in this world of ours their eyes
In March first open shall be wise,
In days of peril firm and brave,
And wear a bloodstone to their grave.