Ah yes. I apologize for giving you the too-simple answer.

The melting points of pure (+) or pure (-) enantiomers should be equal and opposite. Think about stacking a group of identical left- or right- shoes; they interact with each other in a similar way. We call these “homochiral” interactionss. But throw the enantiomer in there and you will have a combination of “homochiral” and “heterochiral” interactions. For example D-tartaric acid is going to hydrogen bond in a slightly different way with another molecule of D-tartaric acid than it will with L-tartaric acid.
The melting point of a mixture tends to be lower for this reason because stacking isn’t efficient.

But it gets more complicated. There are two major ways of forming a solid racemic mixture. You can have crystals which have unit cells containing both the (+)- and (-) enantiomers. This happens about 90% of the time. Or you can have crystals where the (+) and (-) forms crystallize only with each other (like Pasteur observed with potassium sodium tartrate). This is called a conglomerate. These situations will have different melting points as well. They can even be interconverted sometimes upon heating (2-binapthol is a prominent example).

For more detail I highly recommend the bible of stereochemistry, Eliel’s Stereochemistry of Organic Compounds. Page 155 of the edition that I have has a very clear discussion of this topic.

Hi Eric – have you seen this post – https://www.masterorganicchemistry.com/2012/05/23/whats-a-racemic-mixture/
The only physical difference is in the direction in which they rotate plane-polarized light, and in how they interact with a chiral environment.

Sometimes identical molecules are put in as “trick questions”. It’s easy to make identical molecules look superficially different by performing bond rotations or by using a different type of bond projection.