Temperature of jade

Is jade cold to the touch? I read that in an Archie story once; granted Archie comics are not a reliable authority, I’m still curious.

I suppose it depends on the ambient temperature, but as it happens I used a pair of jade chopsticks at home last night and they did indeed feel cool when I picked them up. Providentially I happened to have looked at my thermostat not long before and it read 75F FWIW.

Bet you didn’t expect an answer that specific :slight_smile:

Imperial jade? Jadeite? Nephrite?

That I don’t know. They’re an heirloom from my wife’s side and I’m quite sure no one knows; her grandmother who purchased them in China is long gone.

Jade isn’t exempt from the laws of thermodynamics. It will equalize to the temperature of the room that it is in, just like literally every other substance that isn’t radioactive or undergoing exothermic or endothermic chemical reactions.

This site says one test for phony jade is if it’s cool to the touch.

HVAC guy checking in… Making popcorn and pulling up a lawnchair.

So. When buying a couch the salesman heard me saying to my (now ex) wife that I didn’t want leather since it’s cold in the winter and hot in the summer. He used that same argument. But just like my marble kitchen table, I understand it’s the same temperature, but it feels colder. Which is what the OP asked. If it’s 70 in your house and your body is nearly 100, some things will draw that heat out of your body much faster than others. Sitting on an upholstered, overstuffed, rocking chair, not so much. Leather a bit more. Put your arms on a slab of marble and it’ll feel cool to the touch even though it’s the same temperature as the chair.

That’s what this is about, things that feel cooler feel that way because they draw heat out of your body faster than other things. I assume there’s a technical word, more specific than thermal mass or thermal conductivity for this, but it seems it’s similar to windchill. It’s the same temperature, but it feels colder.

Here is a table with some figures by “Dr. Donald Hoover of the U.S. Geological Survey,” but, as always, I would verify them with a second source before relying on them for anything important.

Now I want jade chopsticks

Marry into the right family is my advice.

I think the operative property here is heat capacity … when this is high, it takes more energy per degree in temperature … in our situation, this means the object takes longer to heat up to body temperature than what we would expect … giving the sense that it is “cold to the touch” … try this at home, put a rock in the freezer overnight and tomorrow morning mama will yell at Billy again for putting stupid things in the freezer …

The link I gave suggests that it is rather the thermal effusivity/thermal inertia that determines the temperature at the contact surface between two bodies.

Assuming the jade is at a room temperature which is colder than your skin temperature, the greater its thermal inertia, the cooler it will feel. According to the table, the value for jade is low compared to diamond or metal, but high compared to, say, glass.

Yeah, it’s the thermal effusivity. But the conductivity component of effusivity does not matter much once it is much more conductive than flesh, and metals generally are. And the heat capacity component doesn’t matter much, either, because solids never get much higher than a couple million joules per cubic meter kelvin. Maybe they get to four million or so. It’s not like you’re going to find something a hundred or a thousand times higher.

Thank you for correcting me … and thanks for the Wiki link, DPRK, that particular article is thin on specifics, but the links from there were all quite interesting … so, effusivity is proportional to the root of capacity? …

I used to make jewelry with semiprecious stones, and I still collect them. A decent test for just about any stone (semiprecious or not) is to touch it or pick it up: stone feels cold and heavy, plastic feels room temperature and light, and glass is somewhere in-between in both categories. This won’t work on porous stones like sandstone or some jaspers, but should work fine for all variants of jade.

Well, we’re not just talking about metals; we’re talking about jade, imitation jade made of some kind of plastic, and other household objects. And household objects have conductivities from well below human flesh to a couple orders of magnitude above (in particular, nearly all plastics are pretty low, and stones like jade are at least medium).

The heat capacity doesn’t vary nearly as much for solids. Wikipedia’s list is pretty sparse, but looks like only a factor of maybe 3 from the lowest to the highest (which is water).

So, really, some objects (like wood) feel warm because they have low thermal conductivity and others (like metals) feel cold because they have high thermal conductivity. The difference in heat capacity isn’t very big and doesn’t matter as much.

My dad always had hunks of unpolished jade lying around (he uses them as paperweights and bookends) and I never noticed anything unusual about them with regards to temperature or conductivity

Returned home from Thanksgiving vacation and spotted the jade chopsticks in the drying rack where I’d left them. Picked them up and there was no perceptible temperature difference. However, I’d just washed my hands in cold water, so I touched them to my cheek–noticeably cooler. Ambient temperature 69F per thermostat.