Hellstone Bar. Hellstone Bars are made from 1 Obsidian and 3 Hellstone at a Hellforge. They are used to create Hellstone Tier items. Items made from Hellstone Bars are the highest quality craftable pre-hardmode items that require bars.
Unitary elastic means that elasticity is equal to 1. In case of price elasticity of demand, e = 1 implies that the percentage change in quantity demanded is equal to the percentage change in price of the commodity. Demand Elasticity is obviously negative. Elasticity = percentage change in quantity demanded / percentagechange in price. Even though perfect real life examples would be tough to list, a close example can be a 1$ increase in price of a good leads to a unit fall in its quantity demanded.
Examples of Price Elasticity of Demand. If the quantity purchased changes more than price change (say, 10%/5%), the product is termed elastic. If the change in quantity purchased is the same as the price change (say, 10%/10% = 1), the product is said to have unit (or unitary) price elasticity.