Both signs in earth
Earth trusts what can be verified, and with the same element on both sides there is no translation problem. Plans are made in terms both parties recognise, and neither is asked to justify caution.
The absent quality is spontaneity. A doubled element leaves the other three uncovered, and here that means the fire of appetite, the air of detachment and the water of unguarded feeling all go unrepresented. The pairing tends towards a life that is well managed and slightly airless, and neither party is temperamentally equipped to notice this happening.
Cardinal and mutable
Capricorn is cardinal and Virgo is mutable, which is the difference that does the work. Capricorn sets the direction; Virgo refines the execution. The division is natural and largely uncontested, which is why the pairing runs smoothly on practical matters.
Where it goes wrong is in the register of the criticism. Virgo corrects the details, in good faith and continuously. Capricorn hears a running assessment of its competence, which is the one subject Capricorn cannot take lightly, and the correction accumulates into something the Virgo partner never intended to say.
Saturn and Mercury
Capricorn is ruled by Saturn, which is slow, cautious and concerned with consequence. Virgo is ruled by Mercury, which is quick and analytic. Having Saturn on one side and Mercury on the other means one partner is thinking faster than the other is willing to commit.
Mercury in an earth sign is not the scattered version of the planet. It is precise and it applies itself to detail. Set against Saturn it produces a pairing that examines everything twice, which is useful in a crisis and exhausting on a Sunday.
Where it grinds
Anxiety, expressed as work. Neither sign puts down a worry, and both convert it into activity, so periods of stress produce two people doing more instead of two people talking.
The second friction is warmth going unstated. Both signs demonstrate affection through practical service rather than through saying anything, and when both parties do that, both can end up unsure that they are loved while each is proving it constantly in a language the other has stopped registering.
Two suns is thin evidence
Shared element is a compatibility of method, not of need. It tells you these two are unlikely to argue about money and tells you nothing about whether they enjoy each other.
What decides that is the Moon in each chart, which sets the private emotional requirement, along with Venus for how affection is given and Mars for how conflict is handled. Sun-sign statements apply to a very large group of people. A comparison of two charts applies to two.
Questions people ask about this
Is Capricorn and Virgo a stable pairing?
Usually, on practical matters. The elements agree and the modalities divide the work without much contest.
What goes wrong between them?
Virgo corrects details continuously and Capricorn hears an assessment of its competence. Neither intends the exchange that way.
What is missing when both partners are earth signs?
Levity and unguarded feeling. Nothing in either temperament supplies it, and neither notices its absence quickly.
How much should we read into the sun signs?
Enough to know the method will match. Not enough to know whether the two people suit each other, which the Moon, Venus and Mars address.