Red and Blue gems don't exist on the Extinction Map of Ark Survival Evolved, but you can use Red and Blue Crystalized Sap in their place. With those, you can craft some of those Aberration items. Blue Crystalized Sap is found throughout the map, outside the city, by harvesting the trees with gray-blue leaves. Red crystalized sap is harvested from the red wood-like spires found in the northern portion of the map. Here are some coordinates for the crystalized sap locations.
|Red Crystalized Sap "trees"|
Red Sap - Northern zone
|Blue Crystalized Sap Trees|
Blue Sap - Throughout the map, but here are some concentrations
Extinction Tree Sap Locations