There are three variations of every ore type. One is the standard type, the other two are better versions. For example, veldspar comes as veldspar, concentrated veldspar and dense veldspar.

The two better versions gives 5% and 10% more minerals when they are refined. In the case of veldspar 333 units of ordinary veldspar gives 1000 units of tritanium while 333 units of concentrated veldspar gives 1050 units of tritanium and 333 units of dense veldspar gives 1100 units of tritanium.

To make life more interesting every ore type has unique adjectives to describe the enhanced versions:

                5%                       10%
Veldspar        Concentrated Veldspar    Dense Veldspar
Scordite        Condensed Scordite       Massive Scordite
Pyroxeres       Solid Pyroxeres          Viscous Pyroxeres
Plagioclase     Azure Plagioclase        Rich Plagioclase
Omber           Silvery Omber            Golden Omber
Kernite         Luminous Kernite         Fiery Kernite
Jaspet          Pure Jaspet              Pristine Jaspet
Hemorphite      Vivid Hemorphite         Radiant Hemorphite
Hedbergite      Vitric Hedbergite        Glazed Hedbergite
Gneiss          Iridescent Gneiss        Prismatic Gneiss
Dark Ochre      Onyx Ochre               Obsidian Ochre
Crokite         Sharp Crokite            Crystalline Crokite
Spodumain       Bright Spodumain         Gleaming Spodumain
Bistot          Triclinic Bistot         Monoclinic Bistot
Arkanor         Crimson Arkonor          Prime Arkonor
Mercoxit        Magma Mercoxit           Vitreous Mercoxit

While beginner miners benefit from going for the 10% versions veteran miners will typically not pay as much attention to it. It is better to go for whatever is in reach than to have to move around all the time.