According to Apple, the iPhone’s LCD screen is made of very hard, optical-quality glass known as
While Apple does not officially use Gorilla Glass on the iPhone, it is an extremely hard material manufactured by Corning Glass, the famous producer of the ceramic tiles that cover the outside surface of all the NASA Space Shuttle orbiters.
Multiple smartphone users have reported that their screens have been scratched by sand. So if you take your phone to the beach frequently, you may wish to invest in a screen protector (or possibly one of those dust-proof, waterproof cases).
If you would like to get technical (or scientific), there is a measurement of hardness called the Mohs Scale of Mineral Hardness.
On a scale of 1 (softest) through 10 (hardest), various minerals are compared.
Glass actually rates at approximately 6 to 7 (according to Wikipedia). Beach sand can consist of a large percentage of quartz, which has a Mohs rating of 7. Any material of equal or greater hardness can produce scratches.
So, if your smartphone (with a glass screen) comes into contact with any of the following materials, it is likely to scratch [Mohs hardness number - material]:
6 – titanium, uranium, glass, silicon, opal
7 – quartz, sand, hardened steel
8 – topaz, cubic zirconia
8.5 – chromium
9 – corundum, silicon carbide (carborundum), tungsten carbide, titanium carbide
9.5 – boron, boron nitride, titanium diboride
10 – diamond, nanocrystalline diamond (hyperdiamond, ultrahard fullerite)
Here are a list of materials that are listed as softer, and should not scratch your smartphone’s screen:
1 – talc, tin, lead, graphite
2 – gold, silver, aluminum
3 – copper
4 – fluorite, iron, nickel
5 – tooth enamel
To conclude. Do you need a screen protector ? Well, look at the list above with hardness between 6 and 10. If you carry any of these things in your pocket, purse or might set your phone on it, you might be well off to get a screen protector. I myself have not used a screen protector on my Droid phone in almost 2 years. I put my phone in my pocket, set it on my desk daily and occasionally drop it on carpeted floors. I have no scratches to this day and my screen still looks great overall. So I will leave the choice up to you