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howto tell apart a mineral and sapphire crystal?


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Also, sapphire and mineral glass is tested by dropping a 2.25 ounce steel ball-bearing on a representative crystal from varying heights until the crystal breaks and the total amount of energy needed to break the glass can be calculated. According to ISO 14368, Part 3, mineral glass must absorb 1600 to 2100x10^-4 Newton-Meters, sapphire is only required to 800 to 1800x10^-4 NM. so saphire can be brittle

You cannot tell the difference between regular mineral crystal and sapphire crystal, except when you attempt a scratch test. Mineral crystal is break resistant but scratches relatively easily; whereas sapphire crystal measures very high at 9 on the Mohs scale, a rating measure of the relative hardness of various materials. Watches are often marked as scratch resistant when fitted with sapphire crystal. Very often, lines and marks on sapphire crystal are mistaken for scratches, which is actually the anti-glare coating fading off after time.

Most newer fine watches are fitted with synthetic sapphire crystals. Sapphire is extremely scratch resistant and this kind of crystal will look like new for years. However, its hardness makes it easier to shatter than mineral crystals. This is usually only an issue if you wear your watch while engaged in very physical activities. In that case, you may want to look for a domed mineral crystal. The major drawback of mineral crystals is that they scratch much easier than sapphire crystals. Some say they also look "cheaper" in the way they reflect light. Others say they look "classic" on certain watches.

a further distinguishing characteristic of sapphire vs mineral is how the droplet behaves if the watch is tilted off the horizontal. On the mineral glass the dropplet will cling and elongate as it starts to drip, leaving a streak. On the sapphire, the droplet remains a ball shape. You can tilt the watch and rotate it and the droplet looks like a little clear ball rolling around on the surface of the crystal

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It takes some time being around both types of crystals to be able to identify them without a tester...most folks may say that if you "flick" the crystal with your finger nail, the sapphire will make a dull "thud" sound and the mineral will make a higher pitched "click" sound"...also, the sapphire crystal feels "denser" when you tap it....other say that a well cleaned sapphire crystal will "round bead" water drops, whereas a mineral crystal will "pool" and "dribble" the droplets.

Hopefully others will chime in...or do a search...I am sure this topic has been discussed ad nauseum?

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Subject: How to Differentiate a Sapphire Crystal from a Mineral Crystal

Posted by GrizzlyMambo on Mon, 03 Oct 2005 22:26:09 GMT

There are two fool-proof tests to differentiate a sapphire crystal from a

mineral crystal:

1) the colour test - look at the edge of the crystal. A sapphire crystal will

have a pinkish hue, a mineral crystal will have a greenish hue.

2) the water test - place large drops of water on the crystal, then tilt the

watch and watch the water slide off. On the sapphire crystal, water will easily

slide off - leaving small well-formed round globules of water on the surface.

On the mineral crystal - most of the water will "stick" to the crystal and the

drops of water will spread across the surface of the crystal to form a

non-uniform "puddle" instead of sliding off.

Try both tests on watches you know have sapphire crystals or mineral crystals

and the results will become immediately apparent to you. Test number 1 doesn't

always work if the edge of the crystal is not a clear polished finish (instead

an opaque powder finish) - and can be confusing before a comparison test is


Edited by ASCIWhite
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At first I found it difficult to tell them apart, but now I can tell and I've been correct every time so far. Theres two ways; 1)Look at the side of the crystal, the mineral has a green/blue tint, whereas the sapphire is 'white' or clear.

2)The other common method I use is to just tap the crystal with my finger nail. The mineral crystal always gives a distinct 'tink' sound which is higher pitched than the sound given off the sapphire, as btocamelo mentioned.

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