Naturally-spawned silverwoods will have shimmerleaf flowers around their base; these will not grow around a sapling-grown silverwood. Shimmerleafs are used to produce the taint-fighting Ethereal Blooms.
Whether naturally spawned or player grown, a silverwood tree can form one or more Pure Nodes within its trunk. When grown with a Hoe of Growth silverwoods have approximately a 58% chance of growing with no aura nodes, a 38% chance of 1 aura node and a 4% chance of growing with 2 aura nodes. The node-bearing logs are marked with large black dots, for the convenience of those without magical vision. As long as any of the node-bearing logs are intact, they will form a patch of Magical Forest biome around the tree, and defend it from Tainted or Eerie biomes.
Thaumonomicon Entry Edit
These rare and magical trees are a wondrous sight. Their leaves shimmer with magical energy and their pale, soft wood is valued for its purifying properties.
The tree's magical nature is such that aura nodes often form within their hearts - this feature alone makes a silverwood sapling a prize beyond measure.
Silverwood has several very important uses: Early in the game, their wood is one of the very few direct sources for Ordo essentia and can be used in the crucible before a centrifuge is available. (It also offers Praecantatio, but that is shared with Greatwood.) The pure nodes that they can produce while growing (see below) are the earliest available means to hold off taint from an area.
As the thaumaturge progresses, they will use silverwood planks to produce "vis filters", a key intermediate component. The vis filter is used for the arcane alembic, and later for the Alchemical Construct (which in turn is used for the centrifuge and Thaumatorium). The logs are used directly for the silverwood wand core, to produce the most advanced wands.
Silverwood saplings are also very useful. When they grow into trees, they have a chance of spawning a pure node within them, although a node will not spawn if there is another pure node too close. This node will slowly convert the area around it into a magical forest, and will both remove taint from the area, and prevent surrounding taint from encroaching. (Magical Forest is one of the three magical biomes where mana beans can be grown.) The magical forest can be reverted by an Ethereal Bloom or a "bare" pure node. Silverwood saplings can be purchased from a Pech Forager.
A silverwood-grown node can be collected as a Node in a Jar. This will require cutting away the wood around it to make room for the "jar" construct. (Be careful with that Axe of the Stream!) Note that the capture will destroy the node's silverwood block, leaving a "bare" pure node. When placed, this will no longer produce magical forest, but it will revert territory changed by any of the invasive magical biomes, back to its original biome. This applies to Tainted Lands, Eerie biomes, or even Magical Forest.