The current table of elements gives a fairly realistic picture of the possible minerals that might be found based on what we know about stability and atomic combinations.
What might be found could be deposits of known minerals which are purified or concentrated in ways not common to Earth.
In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma. The fifth state is the man-made Bose-Einstein condensates.
We might find a pocket of lead gas or solid oxygen. Venus might have naturally occurring liquid gold or barium gas pockets.
I highly doubt unobtanium, adamantium or vibranium exists.
I do believe its possible we might find compounds of known elements in uncommon combinations if we ever explore dead star remnants or bodies formed in nova, supernova and hypernova reactions. It might be possible to find gas and liquid uncommon combinations if we ever explore nebulas or other dust clouds in space.
Heavy water exists on this planet right now. We might find other such 'heavy' liquids on planets/celestial bodies.
Theory of Minerals at High and Ultrahigh Pressures : Structure, Properties, Dynamics, and Phase Transitions
The interest in minerals at extreme conditions is natural: most of the Earth’s interior exists at high pressures (up to 364 GPa) and temperatures (up to ~6000 K). Studying the behaviour, properties,...
Due to how vast the universe is, is it possible to find an element that is not on the periodic table? This question was originally answered on Quora by Steve Harris.
A system of categorization that reflects not just a mineral’s chemistry and crystalline structure, but also the physical, chemical, or biological processes by which it formed, would be capable of recognizing that nanodiamonds from space are fundamentally different to diamonds formed in Earth’s depths.
An evolutionary system of mineralogy: Proposal for a classification of planetary materials
based on natural kind clustering
Robert M. Hazen
Minerals reveal the nature of the co-evolving geosphere and biosphere
through billions of years of Earth history. Mineral classification systems
have the potential to elucidate this rich evolutionary story; however, the
present mineral taxonomy, based as it is on idealized major element chemistry and crystal structure, lacks a temporal aspect, and thus cannot reflect
planetary evolution. A complementary evolutionary system of mineralogy
based on the quantitative recognition of “natural kind clustering” for a wide
range of condensed planetary materials with different paragenetic origins
has the potential to amplify, though not supersede, the present classification system.
Philosophy of mineralogy, classification, mineral evolution, mineral ecology, data-
driven discovery, cluster analysis, natural kinds