Jade vs. Crystal Clear Glass: Which is Harder?

This question comes up a lot in the awards and recognition industry. From a technical perspective, both jade and crystal clear glass are identical in hardness at 470 on the Knoop Hardness test (indentation hardness). On the Moh’s test (scratch hardness), they are also identical at 6 (granite is harder at a 7). The tensile strength for both glass types in their annealed form is also identical at 6,000 PSI.

Although crystal clear glass in our industry (known generically as low-iron glass) and jade glass (known as clear float glass) have the same hardness levels, my years of fabricating experience indicate that jade glass appears marginally harder. The quality of edge polishing that I’m able to achieve with jade glass, in my opinion, is higher. This is because the harder the glass, the higher quality finish we can achieve.

Additionally, jade glass does not scratch quite as easily, which could indicate a slightly higher level of hardness. Experience tells us that although crystal clear glass seems somewhat softer, it makes up for this by the brilliant sparkle it provides due to its better clarity. The slightly softer composition is also shared by many glass etchers that find this glass easier to abrasive etch, as it appears to etch the glass surface faster. Crystal clear glass actually does etch easier, which confirms our own hardness findings.

While both glass types are indeed very hard materials to work with, I give the harder edge to jade by a very thin margin.