“Hardness” of a tarantula’s fangs

[Moakmeister]

I wonder if you could determine the mohs hardness of a tarantula’s fangs by performing scratch tests. I just used one of Regina’s old fangs and scraped it on a window, and it didn’t scratch it, so the hardness is under 5.5.
Apparently, tarantula fangs (along with basically every arthropod’s extremeties) are strengthened with metal deposits at the molecular level. That’s pretty cool. The older the tarantula is, the more metal reinforcements are in the fangs, since more metal is deposited there with each molt. I do wonder if an older T’s fangs could scratch glass.

 

[Salmonsaladsandwich]

I doubt an older tarantula's fangs would be more likely to scratch glass assuming both are adults, as it would have the same material as a younger specimen even if more metal is deposited. The metal found in spider fangs is zinc, which is mostly deposited at the very tips, so my assumption would be that as the spider ages the zinc- rich portion of the fang moves up as opposed to the part already containing a high concentration becoming harder. It would be interesting to see if the fang can scratch anything with a hardness similar to or exceeding pure zinc.

 

[EpicEpic]

If I'm not mistaken I have read that a tarantulas fangs are the hardest part of its exoskeleton.

I do wonder if they are harder on a living tarantula, and how much force it would take to damage the fang against the glass.

 

[KaroKoenig]

Mohs hardness 5.5 is quite a lot. I am ready to bet a month's wage that there's no way a tarantula fang is anywhere near as hard. If you have your Mohs hardness crystal box at hand, start with calcite (3). My guess would be the fangs are somewhere between calcite and fluorite (4).

 

[viper69]

My Ts can bite through diamonds!

@Moakmeister would send a me reference for the metal deposition? This is a new one for me.

 

[KaroKoenig]

Tried it with the fangs of a C. cyaneopubescens, just for shits and giggles. The fang easily scratches gypsum, but is significantly softer than calcite. So we're talking Mohs hardness of 2.5 or a little higher.

The individual wasn't fully grown, the fang is more on the smaller side (~ 6 mm in length).

 

[Salmonsaladsandwich]

Tried it with the fangs of a C. cyaneopubescens, just for shits and giggles. The fang easily scratches gypsum, but is significantly softer than calcite. So we're talking Mohs hardness of 2.5 or a little higher.

The individual wasn't fully grown, the fang is more on the smaller side (~ 6 mm in length).

Zinc has a hardness value of 2.5