This effect is a variation on fencepost's Lord Of The Rings Effect.
You should do the tutorial before you try this one.
Before you can start you need to install a curves-preset.
Download it from mediafire and unzip it into your Gimp user-folder → curves.
01. Create your canvas 800x400px.
02. Fill it with the pattern 'little pluses'. You can get it here:
03. Change the colours with the 'Hue/Brightness/Saturation' Tool.
04. Type your text in a medium grey (#808080).
For this effect to work you will need a font that has irregular edges.
I used the font 'No Fear' at 290px.
05. Duplicate the textlayer, name it bump-map, lock the alpha-channel and drag a gradient from white-black with the Shape: dimpled over the textlayer.
06. Run the Sharpen filter twice or maybe thrice on the bump-map-layer.
07. Make the bump-map-layer invisible and run the bumpmap-filter on the original textlayer.
Make sure the Map-Type is set to: Sinusoidal !
08. Apply the curve-preset to your bevel text.
09. Create a new layer: #2a1c50.
Set the Mode to 'Burn' at 75%.
10. The Dropshadow is the alpha-selected text, filled with black, offset according to the direction of light (i used 3/3) and then treated with some 'Spread' 5-10px (thats under Filters → Noise → Spread).
I set the Mode to 'Grain Merge' 52%.
11. For a little contrast, fill the alpha-selected text with #d0d0d0 on a new transparent layer.
Blur by 5px and reduce Opacity to about 60%.
12. Turn off the Background, Dropshadow and Contrast layer. Then apply 'New From Visible' and turn on the layers again.
On the 'New From Visible' layer apply G'MIC → Artistic → Coloured Pencils with the following values.
Set Output Mode to new Layer !
Set the Mode of this layer to 'Soft Light'. If you want even more texture, duplicate that layer (maybe with the Opacity reduced a bit).
And thats it, hope you found it interesting <3